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LeetCode Editorials

Browse 3217 problem solutions with detailed explanations

Array
String
Hash Table
Math
Dynamic Programming
Sorting
Greedy
Depth-First Search
Binary Search
Matrix
Breadth-First Search
Tree
Bit Manipulation
Two Pointers
Prefix Sum
Heap (Priority Queue)
Simulation
Binary Tree
Stack
Counting
Graph
Sliding Window
Design
Enumeration
Backtracking
Union Find
Linked List
Number Theory
Ordered Set
Monotonic Stack
JavaScript
Trie
Segment Tree
Recursion
Divide and Conquer
Bitmask
Queue
Combinatorics
Memoization
Binary Search Tree
Geometry
Hash Function
Binary Indexed Tree
Topological Sort
Shortest Path
String Matching
Rolling Hash
Game Theory
Interactive
Data Stream
Brainteaser
Monotonic Queue
Pandas
Merge Sort
Randomized
Doubly-Linked List
Counting Sort
Iterator
Concurrency
Database
Quickselect
Probability and Statistics
Suffix Array
Bucket Sort
Line Sweep
Minimum Spanning Tree
Reservoir Sampling
Radix Sort
Eulerian Circuit
Strongly Connected Component
Rejection Sampling
Sort
Biconnected Component
Showing 3217 of 3217 problems
SolutionTagsDifficultyRemark
1. Two Sum
Array
Hash Table
Easy
2. Add Two Numbers
Recursion
Linked List
Math
Medium
3. Longest Substring Without Repeating Characters
Hash Table
String
Sliding Window
Medium
4. Median of Two Sorted Arrays
Array
Binary Search
Divide and Conquer
Hard
5. Longest Palindromic Substring
Two Pointers
String
Dynamic Programming
Medium
6. Zigzag Conversion
String
Medium
7. Reverse Integer
Math
Medium
8. String to Integer (atoi)
String
Medium
9. Palindrome Number
Math
Easy
10. Regular Expression Matching
Recursion
String
Dynamic Programming
Hard
11. Container With Most Water
Greedy
Array
Two Pointers
Medium
12. Integer to Roman
Hash Table
Math
String
Medium
13. Roman to Integer
Hash Table
Math
String
Easy
14. Longest Common Prefix
Trie
Array
String
Easy
15. 3Sum
Array
Two Pointers
Sorting
Medium
16. 3Sum Closest
Array
Two Pointers
Sorting
Medium
17. Letter Combinations of a Phone Number
Hash Table
String
Backtracking
Medium
18. 4Sum
Array
Two Pointers
Sorting
Medium
19. Remove Nth Node From End of List
Linked List
Two Pointers
Medium
20. Valid Parentheses
Stack
String
Easy
21. Merge Two Sorted Lists
Recursion
Linked List
Easy
22. Generate Parentheses
String
Dynamic Programming
Backtracking
Medium
23. Merge k Sorted Lists
Linked List
Divide and Conquer
Heap (Priority Queue)
Merge Sort
Hard
24. Swap Nodes in Pairs
Recursion
Linked List
Medium
25. Reverse Nodes in k-Group
Recursion
Linked List
Hard
26. Remove Duplicates from Sorted Array
Array
Two Pointers
Easy
27. Remove Element
Array
Two Pointers
Easy
28. Find the Index of the First Occurrence in a String
Two Pointers
String
String Matching
Easy
29. Divide Two Integers
Bit Manipulation
Math
Medium
30. Substring with Concatenation of All Words
Hash Table
String
Sliding Window
Hard
31. Next Permutation
Array
Two Pointers
Medium
32. Longest Valid Parentheses
Stack
String
Dynamic Programming
Hard
33. Search in Rotated Sorted Array
Array
Binary Search
Medium
34. Find First and Last Position of Element in Sorted Array
Array
Binary Search
Medium
35. Search Insert Position
Array
Binary Search
Easy
36. Valid Sudoku
Array
Hash Table
Matrix
Medium
37. Sudoku Solver
Array
Hash Table
Backtracking
Matrix
Hard
38. Count and Say
String
Medium
39. Combination Sum
Array
Backtracking
Medium
40. Combination Sum II
Array
Backtracking
Medium
41. First Missing Positive
Array
Hash Table
Hard
42. Trapping Rain Water
Stack
Array
Two Pointers
Dynamic Programming
Monotonic Stack
Hard
43. Multiply Strings
Math
String
Simulation
Medium
44. Wildcard Matching
Greedy
Recursion
String
Dynamic Programming
Hard
45. Jump Game II
Greedy
Array
Dynamic Programming
Medium
46. Permutations
Array
Backtracking
Medium
47. Permutations II
Array
Backtracking
Sorting
Medium
48. Rotate Image
Array
Math
Matrix
Medium
49. Group Anagrams
Array
Hash Table
String
Sorting
Medium
50. Pow(x, n)
Recursion
Math
Medium
51. N-Queens
Array
Backtracking
Hard
52. N-Queens II
Backtracking
Hard
53. Maximum Subarray
Array
Divide and Conquer
Dynamic Programming
Medium
54. Spiral Matrix
Array
Matrix
Simulation
Medium
55. Jump Game
Greedy
Array
Dynamic Programming
Medium
56. Merge Intervals
Array
Sorting
Medium
57. Insert Interval
Array
Medium
58. Length of Last Word
String
Easy
59. Spiral Matrix II
Array
Matrix
Simulation
Medium
60. Permutation Sequence
Recursion
Math
Hard
61. Rotate List
Linked List
Two Pointers
Medium
62. Unique Paths
Math
Dynamic Programming
Combinatorics
Medium
63. Unique Paths II
Array
Dynamic Programming
Matrix
Medium
64. Minimum Path Sum
Array
Dynamic Programming
Matrix
Medium
65. Valid Number
String
Hard
66. Plus One
Array
Math
Easy
67. Add Binary
Bit Manipulation
Math
String
Simulation
Easy
68. Text Justification
Array
String
Simulation
Hard
69. Sqrt(x)
Math
Binary Search
Easy
70. Climbing Stairs
Memoization
Math
Dynamic Programming
Easy
71. Simplify Path
Stack
String
Medium
72. Edit Distance
String
Dynamic Programming
Medium
73. Set Matrix Zeroes
Array
Hash Table
Matrix
Medium
74. Search a 2D Matrix
Array
Binary Search
Matrix
Medium
75. Sort Colors
Array
Two Pointers
Sorting
Medium
76. Minimum Window Substring
Hash Table
String
Sliding Window
Hard
77. Combinations
Backtracking
Medium
78. Subsets
Bit Manipulation
Array
Backtracking
Medium
79. Word Search
Depth-First Search
Array
String
Backtracking
Matrix
Medium
80. Remove Duplicates from Sorted Array II
Array
Two Pointers
Medium
81. Search in Rotated Sorted Array II
Array
Binary Search
Medium
82. Remove Duplicates from Sorted List II
Linked List
Two Pointers
Medium
83. Remove Duplicates from Sorted List
Linked List
Easy
84. Largest Rectangle in Histogram
Stack
Array
Monotonic Stack
Hard
85. Maximal Rectangle
Stack
Array
Dynamic Programming
Matrix
Monotonic Stack
Hard
86. Partition List
Linked List
Two Pointers
Medium
87. Scramble String
String
Dynamic Programming
Hard
88. Merge Sorted Array
Array
Two Pointers
Sorting
Easy
89. Gray Code
Bit Manipulation
Math
Backtracking
Medium
90. Subsets II
Bit Manipulation
Array
Backtracking
Medium
91. Decode Ways
String
Dynamic Programming
Medium
92. Reverse Linked List II
Linked List
Medium
93. Restore IP Addresses
String
Backtracking
Medium
94. Binary Tree Inorder Traversal
Stack
Tree
Depth-First Search
Binary Tree
Easy
95. Unique Binary Search Trees II
Tree
Binary Search Tree
Dynamic Programming
Backtracking
Binary Tree
Medium
96. Unique Binary Search Trees
Tree
Binary Search Tree
Math
Dynamic Programming
Binary Tree
Medium
97. Interleaving String
String
Dynamic Programming
Medium
98. Validate Binary Search Tree
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Medium
99. Recover Binary Search Tree
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Medium
100. Same Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
101. Symmetric Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
102. Binary Tree Level Order Traversal
Tree
Breadth-First Search
Binary Tree
Medium
103. Binary Tree Zigzag Level Order Traversal
Tree
Breadth-First Search
Binary Tree
Medium
104. Maximum Depth of Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
105. Construct Binary Tree from Preorder and Inorder Traversal
Tree
Array
Hash Table
Divide and Conquer
Binary Tree
Medium
106. Construct Binary Tree from Inorder and Postorder Traversal
Tree
Array
Hash Table
Divide and Conquer
Binary Tree
Medium
107. Binary Tree Level Order Traversal II
Tree
Breadth-First Search
Binary Tree
Medium
108. Convert Sorted Array to Binary Search Tree
Tree
Binary Search Tree
Array
Divide and Conquer
Binary Tree
Easy
109. Convert Sorted List to Binary Search Tree
Tree
Binary Search Tree
Linked List
Divide and Conquer
Binary Tree
Medium
110. Balanced Binary Tree
Tree
Depth-First Search
Binary Tree
Easy
111. Minimum Depth of Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
112. Path Sum
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
113. Path Sum II
Tree
Depth-First Search
Backtracking
Binary Tree
Medium
114. Flatten Binary Tree to Linked List
Stack
Tree
Depth-First Search
Linked List
Binary Tree
Medium
115. Distinct Subsequences
String
Dynamic Programming
Hard
116. Populating Next Right Pointers in Each Node
Tree
Depth-First Search
Breadth-First Search
Linked List
Binary Tree
Medium
117. Populating Next Right Pointers in Each Node II
Tree
Depth-First Search
Breadth-First Search
Linked List
Binary Tree
Medium
118. Pascal's Triangle
Array
Dynamic Programming
Easy
119. Pascal's Triangle II
Array
Dynamic Programming
Easy
120. Triangle
Array
Dynamic Programming
Medium
121. Best Time to Buy and Sell Stock
Array
Dynamic Programming
Easy
122. Best Time to Buy and Sell Stock II
Greedy
Array
Dynamic Programming
Medium
123. Best Time to Buy and Sell Stock III
Array
Dynamic Programming
Hard
124. Binary Tree Maximum Path Sum
Tree
Depth-First Search
Dynamic Programming
Binary Tree
Hard
125. Valid Palindrome
Two Pointers
String
Easy
126. Word Ladder II
Breadth-First Search
Hash Table
String
Backtracking
Hard
127. Word Ladder
Breadth-First Search
Hash Table
String
Hard
128. Longest Consecutive Sequence
Union Find
Array
Hash Table
Medium
129. Sum Root to Leaf Numbers
Tree
Depth-First Search
Binary Tree
Medium
130. Surrounded Regions
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
131. Palindrome Partitioning
String
Dynamic Programming
Backtracking
Medium
132. Palindrome Partitioning II
String
Dynamic Programming
Hard
133. Clone Graph
Depth-First Search
Breadth-First Search
Graph
Hash Table
Medium
134. Gas Station
Greedy
Array
Medium
135. Candy
Greedy
Array
Hard
136. Single Number
Bit Manipulation
Array
Easy
137. Single Number II
Bit Manipulation
Array
Medium
138. Copy List with Random Pointer
Hash Table
Linked List
Medium
139. Word Break
Trie
Memoization
Array
Hash Table
String
Dynamic Programming
Medium
140. Word Break II
Trie
Memoization
Array
Hash Table
String
Dynamic Programming
Backtracking
Hard
141. Linked List Cycle
Hash Table
Linked List
Two Pointers
Easy
142. Linked List Cycle II
Hash Table
Linked List
Two Pointers
Medium
143. Reorder List
Stack
Recursion
Linked List
Two Pointers
Medium
144. Binary Tree Preorder Traversal
Stack
Tree
Depth-First Search
Binary Tree
Easy
145. Binary Tree Postorder Traversal
Stack
Tree
Depth-First Search
Binary Tree
Easy
146. LRU Cache
Design
Hash Table
Linked List
Doubly-Linked List
Medium
147. Insertion Sort List
Linked List
Sorting
Medium
148. Sort List
Linked List
Two Pointers
Divide and Conquer
Sorting
Merge Sort
Medium
149. Max Points on a Line
Geometry
Array
Hash Table
Math
Hard
150. Evaluate Reverse Polish Notation
Stack
Array
Math
Medium
151. Reverse Words in a String
Two Pointers
String
Medium
152. Maximum Product Subarray
Array
Dynamic Programming
Medium
153. Find Minimum in Rotated Sorted Array
Array
Binary Search
Medium
154. Find Minimum in Rotated Sorted Array II
Array
Binary Search
Hard
155. Min Stack
Stack
Design
Medium
156. Binary Tree Upside Down
Tree
Depth-First Search
Binary Tree
Medium
157. Read N Characters Given Read4
Array
Interactive
Simulation
Easy
158. Read N Characters Given read4 II - Call Multiple Times
Array
Interactive
Simulation
Hard
159. Longest Substring with At Most Two Distinct Characters
Hash Table
String
Sliding Window
Medium
160. Intersection of Two Linked Lists
Hash Table
Linked List
Two Pointers
Easy
161. One Edit Distance
Two Pointers
String
Medium
162. Find Peak Element
Array
Binary Search
Medium
163. Missing Ranges
Array
Easy
164. Maximum Gap
Array
Bucket Sort
Radix Sort
Sorting
Medium
165. Compare Version Numbers
Two Pointers
String
Medium
166. Fraction to Recurring Decimal
Hash Table
Math
String
Medium
167. Two Sum II - Input Array Is Sorted
Array
Two Pointers
Binary Search
Medium
168. Excel Sheet Column Title
Math
String
Easy
169. Majority Element
Array
Hash Table
Divide and Conquer
Counting
Sorting
Easy
170. Two Sum III - Data structure design
Design
Array
Hash Table
Two Pointers
Data Stream
Easy
171. Excel Sheet Column Number
Math
String
Easy
172. Factorial Trailing Zeroes
Math
Medium
173. Binary Search Tree Iterator
Stack
Tree
Design
Binary Search Tree
Binary Tree
Iterator
Medium
174. Dungeon Game
Array
Dynamic Programming
Matrix
Hard
179. Largest Number
Greedy
Array
String
Sorting
Medium
186. Reverse Words in a String II
Two Pointers
String
Medium
187. Repeated DNA Sequences
Bit Manipulation
Hash Table
String
Sliding Window
Hash Function
Rolling Hash
Medium
188. Best Time to Buy and Sell Stock IV
Array
Dynamic Programming
Hard
189. Rotate Array
Array
Math
Two Pointers
Medium
190. Reverse Bits
Bit Manipulation
Divide and Conquer
Easy
191. Number of 1 Bits
Bit Manipulation
Divide and Conquer
Easy
198. House Robber
Array
Dynamic Programming
Medium
199. Binary Tree Right Side View
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
200. Number of Islands
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
201. Bitwise AND of Numbers Range
Bit Manipulation
Medium
202. Happy Number
Hash Table
Math
Two Pointers
Easy
203. Remove Linked List Elements
Recursion
Linked List
Easy
204. Count Primes
Array
Math
Enumeration
Number Theory
Medium
205. Isomorphic Strings
Hash Table
String
Easy
206. Reverse Linked List
Recursion
Linked List
Easy
207. Course Schedule
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Medium
208. Implement Trie (Prefix Tree)
Design
Trie
Hash Table
String
Medium
209. Minimum Size Subarray Sum
Array
Binary Search
Prefix Sum
Sliding Window
Medium
210. Course Schedule II
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Medium
211. Design Add and Search Words Data Structure
Depth-First Search
Design
Trie
String
Medium
212. Word Search II
Trie
Array
String
Backtracking
Matrix
Hard
213. House Robber II
Array
Dynamic Programming
Medium
214. Shortest Palindrome
String
String Matching
Hash Function
Rolling Hash
Hard
215. Kth Largest Element in an Array
Array
Divide and Conquer
Quickselect
Sorting
Heap (Priority Queue)
Medium
216. Combination Sum III
Array
Backtracking
Medium
217. Contains Duplicate
Array
Hash Table
Sorting
Easy
218. The Skyline Problem
Binary Indexed Tree
Segment Tree
Array
Divide and Conquer
Ordered Set
Line Sweep
Heap (Priority Queue)
Hard
219. Contains Duplicate II
Array
Hash Table
Sliding Window
Easy
220. Contains Duplicate III
Array
Bucket Sort
Ordered Set
Sorting
Sliding Window
Hard
221. Maximal Square
Array
Dynamic Programming
Matrix
Medium
222. Count Complete Tree Nodes
Bit Manipulation
Tree
Binary Search
Binary Tree
Easy
223. Rectangle Area
Geometry
Math
Medium
224. Basic Calculator
Stack
Recursion
Math
String
Hard
225. Implement Stack using Queues
Stack
Design
Queue
Easy
226. Invert Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
227. Basic Calculator II
Stack
Math
String
Medium
228. Summary Ranges
Array
Easy
229. Majority Element II
Array
Hash Table
Counting
Sorting
Medium
230. Kth Smallest Element in a BST
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Medium
231. Power of Two
Bit Manipulation
Recursion
Math
Easy
232. Implement Queue using Stacks
Stack
Design
Queue
Easy
233. Number of Digit One
Recursion
Math
Dynamic Programming
Hard
234. Palindrome Linked List
Stack
Recursion
Linked List
Two Pointers
Easy
235. Lowest Common Ancestor of a Binary Search Tree
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Medium
236. Lowest Common Ancestor of a Binary Tree
Tree
Depth-First Search
Binary Tree
Medium
237. Delete Node in a Linked List
Linked List
Medium
238. Product of Array Except Self
Array
Prefix Sum
Medium
239. Sliding Window Maximum
Queue
Array
Sliding Window
Monotonic Queue
Heap (Priority Queue)
Hard
240. Search a 2D Matrix II
Array
Binary Search
Divide and Conquer
Matrix
Medium
241. Different Ways to Add Parentheses
Recursion
Memoization
Math
String
Dynamic Programming
Medium
242. Valid Anagram
Hash Table
String
Sorting
Easy
243. Shortest Word Distance
Array
String
Easy
244. Shortest Word Distance II
Design
Array
Hash Table
Two Pointers
String
Medium
245. Shortest Word Distance III
Array
String
Medium
246. Strobogrammatic Number
Hash Table
Two Pointers
String
Easy
247. Strobogrammatic Number II
Recursion
Array
String
Medium
248. Strobogrammatic Number III
Recursion
Array
String
Hard
249. Group Shifted Strings
Array
Hash Table
String
Medium
250. Count Univalue Subtrees
Tree
Depth-First Search
Binary Tree
Medium
251. Flatten 2D Vector
Design
Array
Two Pointers
Iterator
Medium
252. Meeting Rooms
Array
Sorting
Easy
253. Meeting Rooms II
Greedy
Array
Two Pointers
Prefix Sum
Sorting
Heap (Priority Queue)
Medium
254. Factor Combinations
Backtracking
Medium
255. Verify Preorder Sequence in Binary Search Tree
Stack
Tree
Binary Search Tree
Recursion
Array
Binary Tree
Monotonic Stack
Medium
256. Paint House
Array
Dynamic Programming
Medium
257. Binary Tree Paths
Tree
Depth-First Search
String
Backtracking
Binary Tree
Easy
258. Add Digits
Math
Number Theory
Simulation
Easy
259. 3Sum Smaller
Array
Two Pointers
Binary Search
Sorting
Medium
260. Single Number III
Bit Manipulation
Array
Medium
261. Graph Valid Tree
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
263. Ugly Number
Math
Easy
264. Ugly Number II
Hash Table
Math
Dynamic Programming
Heap (Priority Queue)
Medium
265. Paint House II
Array
Dynamic Programming
Hard
266. Palindrome Permutation
Bit Manipulation
Hash Table
String
Easy
267. Palindrome Permutation II
Hash Table
String
Backtracking
Medium
268. Missing Number
Bit Manipulation
Array
Hash Table
Math
Binary Search
Sorting
Easy
269. Alien Dictionary
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Array
String
Hard
270. Closest Binary Search Tree Value
Tree
Depth-First Search
Binary Search Tree
Binary Search
Binary Tree
Easy
271. Encode and Decode Strings
Design
Array
String
Medium
272. Closest Binary Search Tree Value II
Stack
Tree
Depth-First Search
Binary Search Tree
Two Pointers
Binary Tree
Heap (Priority Queue)
Hard
273. Integer to English Words
Recursion
Math
String
Hard
274. H-Index
Array
Counting Sort
Sorting
Medium
275. H-Index II
Array
Binary Search
Medium
276. Paint Fence
Dynamic Programming
Medium
277. Find the Celebrity
Graph
Two Pointers
Interactive
Medium
278. First Bad Version
Binary Search
Interactive
Easy
279. Perfect Squares
Breadth-First Search
Math
Dynamic Programming
Medium
280. Wiggle Sort
Greedy
Array
Sorting
Medium
281. Zigzag Iterator
Design
Queue
Array
Iterator
Medium
282. Expression Add Operators
Math
String
Backtracking
Hard
283. Move Zeroes
Array
Two Pointers
Easy
284. Peeking Iterator
Design
Array
Iterator
Medium
285. Inorder Successor in BST
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Medium
286. Walls and Gates
Breadth-First Search
Array
Matrix
Medium
287. Find the Duplicate Number
Bit Manipulation
Array
Two Pointers
Binary Search
Medium
288. Unique Word Abbreviation
Design
Array
Hash Table
String
Medium
289. Game of Life
Array
Matrix
Simulation
Medium
290. Word Pattern
Hash Table
String
Easy
291. Word Pattern II
Hash Table
String
Backtracking
Medium
292. Nim Game
Brainteaser
Math
Game Theory
Easy
293. Flip Game
String
Easy
294. Flip Game II
Memoization
Math
Dynamic Programming
Backtracking
Game Theory
Medium
295. Find Median from Data Stream
Design
Two Pointers
Data Stream
Sorting
Heap (Priority Queue)
Hard
296. Best Meeting Point
Array
Math
Matrix
Sorting
Hard
297. Serialize and Deserialize Binary Tree
Tree
Depth-First Search
Breadth-First Search
Design
String
Binary Tree
Hard
298. Binary Tree Longest Consecutive Sequence
Tree
Depth-First Search
Binary Tree
Medium
299. Bulls and Cows
Hash Table
String
Counting
Medium
300. Longest Increasing Subsequence
Array
Binary Search
Dynamic Programming
Medium
301. Remove Invalid Parentheses
Breadth-First Search
String
Backtracking
Hard
302. Smallest Rectangle Enclosing Black Pixels
Depth-First Search
Breadth-First Search
Array
Binary Search
Matrix
Hard
303. Range Sum Query - Immutable
Design
Array
Prefix Sum
Easy
304. Range Sum Query 2D - Immutable
Design
Array
Matrix
Prefix Sum
Medium
305. Number of Islands II
Union Find
Array
Hash Table
Hard
306. Additive Number
String
Backtracking
Medium
307. Range Sum Query - Mutable
Design
Binary Indexed Tree
Segment Tree
Array
Divide and Conquer
Medium
308. Range Sum Query 2D - Mutable
Design
Binary Indexed Tree
Segment Tree
Array
Matrix
Medium
309. Best Time to Buy and Sell Stock with Cooldown
Array
Dynamic Programming
Medium
310. Minimum Height Trees
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Medium
311. Sparse Matrix Multiplication
Array
Hash Table
Matrix
Medium
312. Burst Balloons
Array
Dynamic Programming
Hard
313. Super Ugly Number
Array
Math
Dynamic Programming
Medium
314. Binary Tree Vertical Order Traversal
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Sorting
Medium
315. Count of Smaller Numbers After Self
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Hard
316. Remove Duplicate Letters
Stack
Greedy
String
Monotonic Stack
Medium
317. Shortest Distance from All Buildings
Breadth-First Search
Array
Matrix
Hard
318. Maximum Product of Word Lengths
Bit Manipulation
Array
String
Medium
319. Bulb Switcher
Brainteaser
Math
Medium
320. Generalized Abbreviation
Bit Manipulation
String
Backtracking
Medium
321. Create Maximum Number
Stack
Greedy
Array
Two Pointers
Monotonic Stack
Hard
322. Coin Change
Breadth-First Search
Array
Dynamic Programming
Medium
323. Number of Connected Components in an Undirected Graph
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
324. Wiggle Sort II
Greedy
Array
Divide and Conquer
Quickselect
Sorting
Medium
325. Maximum Size Subarray Sum Equals k
Array
Hash Table
Prefix Sum
Medium
326. Power of Three
Recursion
Math
Easy
327. Count of Range Sum
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Hard
328. Odd Even Linked List
Linked List
Medium
329. Longest Increasing Path in a Matrix
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Memoization
Array
Dynamic Programming
Matrix
Hard
330. Patching Array
Greedy
Array
Hard
331. Verify Preorder Serialization of a Binary Tree
Stack
Tree
String
Binary Tree
Medium
332. Reconstruct Itinerary
Depth-First Search
Graph
Eulerian Circuit
Hard
333. Largest BST Subtree
Tree
Depth-First Search
Binary Search Tree
Dynamic Programming
Binary Tree
Medium
334. Increasing Triplet Subsequence
Greedy
Array
Medium
335. Self Crossing
Geometry
Array
Math
Hard
336. Palindrome Pairs
Trie
Array
Hash Table
String
Hard
337. House Robber III
Tree
Depth-First Search
Dynamic Programming
Binary Tree
Medium
338. Counting Bits
Bit Manipulation
Dynamic Programming
Easy
339. Nested List Weight Sum
Depth-First Search
Breadth-First Search
Medium
340. Longest Substring with At Most K Distinct Characters
Hash Table
String
Sliding Window
Medium
341. Flatten Nested List Iterator
Stack
Tree
Depth-First Search
Design
Queue
Iterator
Medium
342. Power of Four
Bit Manipulation
Recursion
Math
Easy
343. Integer Break
Math
Dynamic Programming
Medium
344. Reverse String
Two Pointers
String
Easy
345. Reverse Vowels of a String
Two Pointers
String
Easy
346. Moving Average from Data Stream
Design
Queue
Array
Data Stream
Easy
347. Top K Frequent Elements
Array
Hash Table
Divide and Conquer
Bucket Sort
Counting
Quickselect
Sorting
Heap (Priority Queue)
Medium
348. Design Tic-Tac-Toe
Design
Array
Hash Table
Matrix
Simulation
Medium
349. Intersection of Two Arrays
Array
Hash Table
Two Pointers
Binary Search
Sorting
Easy
350. Intersection of Two Arrays II
Array
Hash Table
Two Pointers
Binary Search
Sorting
Easy
351. Android Unlock Patterns
Bit Manipulation
Dynamic Programming
Backtracking
Bitmask
Medium
352. Data Stream as Disjoint Intervals
Design
Binary Search
Ordered Set
Hard
353. Design Snake Game
Design
Queue
Array
Hash Table
Simulation
Medium
354. Russian Doll Envelopes
Array
Binary Search
Dynamic Programming
Sorting
Hard
355. Design Twitter
Design
Hash Table
Linked List
Heap (Priority Queue)
Medium
356. Line Reflection
Array
Hash Table
Math
Medium
357. Count Numbers with Unique Digits
Math
Dynamic Programming
Backtracking
Medium
358. Rearrange String k Distance Apart
Greedy
Hash Table
String
Counting
Sorting
Heap (Priority Queue)
Hard
359. Logger Rate Limiter
Design
Hash Table
Data Stream
Easy
360. Sort Transformed Array
Array
Math
Two Pointers
Sorting
Medium
361. Bomb Enemy
Array
Dynamic Programming
Matrix
Medium
362. Design Hit Counter
Design
Queue
Array
Binary Search
Data Stream
Medium
363. Max Sum of Rectangle No Larger Than K
Array
Binary Search
Matrix
Ordered Set
Prefix Sum
Hard
364. Nested List Weight Sum II
Stack
Depth-First Search
Breadth-First Search
Medium
365. Water and Jug Problem
Depth-First Search
Breadth-First Search
Math
Medium
366. Find Leaves of Binary Tree
Tree
Depth-First Search
Binary Tree
Medium
367. Valid Perfect Square
Math
Binary Search
Easy
368. Largest Divisible Subset
Array
Math
Dynamic Programming
Sorting
Medium
369. Plus One Linked List
Linked List
Math
Medium
370. Range Addition
Array
Prefix Sum
Medium
371. Sum of Two Integers
Bit Manipulation
Math
Medium
372. Super Pow
Math
Divide and Conquer
Medium
373. Find K Pairs with Smallest Sums
Array
Heap (Priority Queue)
Medium
374. Guess Number Higher or Lower
Binary Search
Interactive
Easy
375. Guess Number Higher or Lower II
Math
Dynamic Programming
Game Theory
Medium
376. Wiggle Subsequence
Greedy
Array
Dynamic Programming
Medium
377. Combination Sum IV
Array
Dynamic Programming
Medium
378. Kth Smallest Element in a Sorted Matrix
Array
Binary Search
Matrix
Sorting
Heap (Priority Queue)
Medium
379. Design Phone Directory
Design
Queue
Array
Hash Table
Linked List
Medium
380. Insert Delete GetRandom O(1)
Design
Array
Hash Table
Math
Randomized
Medium
381. Insert Delete GetRandom O(1) - Duplicates allowed
Design
Array
Hash Table
Math
Randomized
Hard
382. Linked List Random Node
Reservoir Sampling
Linked List
Math
Randomized
Medium
383. Ransom Note
Hash Table
String
Counting
Easy
384. Shuffle an Array
Design
Array
Math
Randomized
Medium
385. Mini Parser
Stack
Depth-First Search
String
Medium
386. Lexicographical Numbers
Depth-First Search
Trie
Medium
387. First Unique Character in a String
Queue
Hash Table
String
Counting
Easy
388. Longest Absolute File Path
Stack
Depth-First Search
String
Medium
389. Find the Difference
Bit Manipulation
Hash Table
String
Sorting
Easy
390. Elimination Game
Recursion
Math
Medium
391. Perfect Rectangle
Geometry
Array
Hash Table
Math
Line Sweep
Hard
392. Is Subsequence
Two Pointers
String
Dynamic Programming
Easy
393. UTF-8 Validation
Bit Manipulation
Array
Medium
394. Decode String
Stack
Recursion
String
Medium
395. Longest Substring with At Least K Repeating Characters
Hash Table
String
Divide and Conquer
Sliding Window
Medium
396. Rotate Function
Array
Math
Dynamic Programming
Medium
397. Integer Replacement
Greedy
Bit Manipulation
Memoization
Dynamic Programming
Medium
398. Random Pick Index
Reservoir Sampling
Hash Table
Math
Randomized
Medium
399. Evaluate Division
Depth-First Search
Breadth-First Search
Union Find
Graph
Array
String
Shortest Path
Medium
400. Nth Digit
Math
Binary Search
Medium
401. Binary Watch
Bit Manipulation
Backtracking
Easy
402. Remove K Digits
Stack
Greedy
String
Monotonic Stack
Medium
403. Frog Jump
Array
Dynamic Programming
Hard
404. Sum of Left Leaves
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
405. Convert a Number to Hexadecimal
Bit Manipulation
Math
String
Easy
406. Queue Reconstruction by Height
Binary Indexed Tree
Segment Tree
Array
Sorting
Medium
407. Trapping Rain Water II
Breadth-First Search
Array
Matrix
Heap (Priority Queue)
Hard
408. Valid Word Abbreviation
Two Pointers
String
Easy
409. Longest Palindrome
Greedy
Hash Table
String
Easy
410. Split Array Largest Sum
Greedy
Array
Binary Search
Dynamic Programming
Prefix Sum
Hard
411. Minimum Unique Word Abbreviation
Bit Manipulation
Array
String
Backtracking
Hard
412. Fizz Buzz
Math
String
Simulation
Easy
413. Arithmetic Slices
Array
Dynamic Programming
Sliding Window
Medium
414. Third Maximum Number
Array
Sorting
Easy
415. Add Strings
Math
String
Simulation
Easy
416. Partition Equal Subset Sum
Array
Dynamic Programming
Medium
417. Pacific Atlantic Water Flow
Depth-First Search
Breadth-First Search
Array
Matrix
Medium
418. Sentence Screen Fitting
Array
String
Dynamic Programming
Medium
419. Battleships in a Board
Depth-First Search
Array
Matrix
Medium
420. Strong Password Checker
Greedy
String
Heap (Priority Queue)
Hard
421. Maximum XOR of Two Numbers in an Array
Bit Manipulation
Trie
Array
Hash Table
Medium
422. Valid Word Square
Array
Matrix
Easy
423. Reconstruct Original Digits from English
Hash Table
Math
String
Medium
424. Longest Repeating Character Replacement
Hash Table
String
Sliding Window
Medium
425. Word Squares
Trie
Array
String
Backtracking
Hard
426. Convert Binary Search Tree to Sorted Doubly Linked List
Stack
Tree
Depth-First Search
Binary Search Tree
Linked List
Binary Tree
Doubly-Linked List
Medium
427. Construct Quad Tree
Tree
Array
Divide and Conquer
Matrix
Medium
428. Serialize and Deserialize N-ary Tree
Tree
Depth-First Search
Breadth-First Search
String
Hard
429. N-ary Tree Level Order Traversal
Tree
Breadth-First Search
Medium
430. Flatten a Multilevel Doubly Linked List
Depth-First Search
Linked List
Doubly-Linked List
Medium
431. Encode N-ary Tree to Binary Tree
Tree
Depth-First Search
Breadth-First Search
Design
Binary Tree
Hard
432. All O`one Data Structure
Design
Hash Table
Linked List
Doubly-Linked List
Hard
433. Minimum Genetic Mutation
Breadth-First Search
Hash Table
String
Medium
434. Number of Segments in a String
String
Easy
435. Non-overlapping Intervals
Greedy
Array
Dynamic Programming
Sorting
Medium
436. Find Right Interval
Array
Binary Search
Sorting
Medium
437. Path Sum III
Tree
Depth-First Search
Binary Tree
Medium
438. Find All Anagrams in a String
Hash Table
String
Sliding Window
Medium
439. Ternary Expression Parser
Stack
Recursion
String
Medium
440. K-th Smallest in Lexicographical Order
Trie
Hard
441. Arranging Coins
Math
Binary Search
Easy
442. Find All Duplicates in an Array
Array
Hash Table
Medium
443. String Compression
Two Pointers
String
Medium
444. Sequence Reconstruction
Graph
Topological Sort
Array
Medium
445. Add Two Numbers II
Stack
Linked List
Math
Medium
446. Arithmetic Slices II - Subsequence
Array
Dynamic Programming
Hard
447. Number of Boomerangs
Array
Hash Table
Math
Medium
448. Find All Numbers Disappeared in an Array
Array
Hash Table
Easy
449. Serialize and Deserialize BST
Tree
Depth-First Search
Breadth-First Search
Design
Binary Search Tree
String
Binary Tree
Medium
450. Delete Node in a BST
Tree
Binary Search Tree
Binary Tree
Medium
451. Sort Characters By Frequency
Hash Table
String
Bucket Sort
Counting
Sorting
Heap (Priority Queue)
Medium
452. Minimum Number of Arrows to Burst Balloons
Greedy
Array
Sorting
Medium
453. Minimum Moves to Equal Array Elements
Array
Math
Medium
454. 4Sum II
Array
Hash Table
Medium
455. Assign Cookies
Greedy
Array
Two Pointers
Sorting
Easy
456. 132 Pattern
Stack
Array
Binary Search
Ordered Set
Monotonic Stack
Medium
457. Circular Array Loop
Array
Hash Table
Two Pointers
Medium
458. Poor Pigs
Math
Dynamic Programming
Combinatorics
Hard
459. Repeated Substring Pattern
String
String Matching
Easy
460. LFU Cache
Design
Hash Table
Linked List
Doubly-Linked List
Hard
461. Hamming Distance
Bit Manipulation
Easy
462. Minimum Moves to Equal Array Elements II
Array
Math
Sorting
Medium
463. Island Perimeter
Depth-First Search
Breadth-First Search
Array
Matrix
Easy
464. Can I Win
Bit Manipulation
Memoization
Math
Dynamic Programming
Bitmask
Game Theory
Medium
465. Optimal Account Balancing
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Hard
466. Count The Repetitions
String
Dynamic Programming
Hard
467. Unique Substrings in Wraparound String
String
Dynamic Programming
Medium
468. Validate IP Address
String
Medium
469. Convex Polygon
Geometry
Array
Math
Medium
470. Implement Rand10() Using Rand7()
Math
Rejection Sampling
Probability and Statistics
Randomized
Medium
471. Encode String with Shortest Length
String
Dynamic Programming
Hard
472. Concatenated Words
Depth-First Search
Trie
Array
String
Dynamic Programming
Sorting
Hard
473. Matchsticks to Square
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Medium
474. Ones and Zeroes
Array
String
Dynamic Programming
Medium
475. Heaters
Array
Two Pointers
Binary Search
Sorting
Medium
476. Number Complement
Bit Manipulation
Easy
477. Total Hamming Distance
Bit Manipulation
Array
Math
Medium
478. Generate Random Point in a Circle
Geometry
Math
Rejection Sampling
Randomized
Medium
479. Largest Palindrome Product
Math
Enumeration
Hard
480. Sliding Window Median
Array
Hash Table
Sliding Window
Heap (Priority Queue)
Hard
481. Magical String
Two Pointers
String
Medium
482. License Key Formatting
String
Easy
483. Smallest Good Base
Math
Binary Search
Hard
484. Find Permutation
Stack
Greedy
Array
String
Medium
485. Max Consecutive Ones
Array
Easy
486. Predict the Winner
Recursion
Array
Math
Dynamic Programming
Game Theory
Medium
487. Max Consecutive Ones II
Array
Dynamic Programming
Sliding Window
Medium
488. Zuma Game
Stack
Breadth-First Search
Memoization
String
Dynamic Programming
Hard
489. Robot Room Cleaner
Backtracking
Interactive
Hard
490. The Maze
Depth-First Search
Breadth-First Search
Array
Matrix
Medium
491. Non-decreasing Subsequences
Bit Manipulation
Array
Hash Table
Backtracking
Medium
492. Construct the Rectangle
Math
Easy
493. Reverse Pairs
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Hard
494. Target Sum
Array
Dynamic Programming
Backtracking
Medium
495. Teemo Attacking
Array
Simulation
Easy
496. Next Greater Element I
Stack
Array
Hash Table
Monotonic Stack
Easy
497. Random Point in Non-overlapping Rectangles
Reservoir Sampling
Array
Math
Binary Search
Ordered Set
Prefix Sum
Randomized
Medium
498. Diagonal Traverse
Array
Matrix
Simulation
Medium
499. The Maze III
Depth-First Search
Breadth-First Search
Graph
Array
String
Matrix
Shortest Path
Heap (Priority Queue)
Hard
500. Keyboard Row
Array
Hash Table
String
Easy
501. Find Mode in Binary Search Tree
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Easy
502. IPO
Greedy
Array
Sorting
Heap (Priority Queue)
Hard
503. Next Greater Element II
Stack
Array
Monotonic Stack
Medium
504. Base 7
Math
String
Easy
505. The Maze II
Depth-First Search
Breadth-First Search
Graph
Array
Matrix
Shortest Path
Heap (Priority Queue)
Medium
506. Relative Ranks
Array
Sorting
Heap (Priority Queue)
Easy
507. Perfect Number
Math
Easy
508. Most Frequent Subtree Sum
Tree
Depth-First Search
Hash Table
Binary Tree
Medium
509. Fibonacci Number
Recursion
Memoization
Math
Dynamic Programming
Easy
510. Inorder Successor in BST II
Tree
Binary Search Tree
Binary Tree
Medium
513. Find Bottom Left Tree Value
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
514. Freedom Trail
Depth-First Search
Breadth-First Search
String
Dynamic Programming
Hard
515. Find Largest Value in Each Tree Row
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
516. Longest Palindromic Subsequence
String
Dynamic Programming
Medium
517. Super Washing Machines
Greedy
Array
Hard
518. Coin Change II
Array
Dynamic Programming
Medium
519. Random Flip Matrix
Reservoir Sampling
Hash Table
Math
Randomized
Medium
520. Detect Capital
String
Easy
521. Longest Uncommon Subsequence I
String
Easy
522. Longest Uncommon Subsequence II
Array
Hash Table
Two Pointers
String
Sorting
Medium
523. Continuous Subarray Sum
Array
Hash Table
Math
Prefix Sum
Medium
524. Longest Word in Dictionary through Deleting
Array
Two Pointers
String
Sorting
Medium
525. Contiguous Array
Array
Hash Table
Prefix Sum
Medium
526. Beautiful Arrangement
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Medium
527. Word Abbreviation
Greedy
Trie
Array
String
Sorting
Hard
528. Random Pick with Weight
Array
Math
Binary Search
Prefix Sum
Randomized
Medium
529. Minesweeper
Depth-First Search
Breadth-First Search
Array
Matrix
Medium
530. Minimum Absolute Difference in BST
Tree
Depth-First Search
Breadth-First Search
Binary Search Tree
Binary Tree
Easy
531. Lonely Pixel I
Array
Hash Table
Matrix
Medium
532. K-diff Pairs in an Array
Array
Hash Table
Two Pointers
Binary Search
Sorting
Medium
533. Lonely Pixel II
Array
Hash Table
Matrix
Medium
535. Encode and Decode TinyURL
Design
Hash Table
String
Hash Function
Medium
536. Construct Binary Tree from String
Stack
Tree
Depth-First Search
String
Binary Tree
Medium
537. Complex Number Multiplication
Math
String
Simulation
Medium
538. Convert BST to Greater Tree
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Medium
539. Minimum Time Difference
Array
Math
String
Sorting
Medium
540. Single Element in a Sorted Array
Array
Binary Search
Medium
541. Reverse String II
Two Pointers
String
Easy
542. 01 Matrix
Breadth-First Search
Array
Dynamic Programming
Matrix
Medium
543. Diameter of Binary Tree
Tree
Depth-First Search
Binary Tree
Easy
544. Output Contest Matches
Recursion
String
Simulation
Medium
545. Boundary of Binary Tree
Tree
Depth-First Search
Binary Tree
Medium
546. Remove Boxes
Memoization
Array
Dynamic Programming
Hard
547. Number of Provinces
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
548. Split Array with Equal Sum
Array
Hash Table
Prefix Sum
Hard
549. Binary Tree Longest Consecutive Sequence II
Tree
Depth-First Search
Binary Tree
Medium
551. Student Attendance Record I
String
Easy
552. Student Attendance Record II
Dynamic Programming
Hard
553. Optimal Division
Array
Math
Dynamic Programming
Medium
554. Brick Wall
Array
Hash Table
Medium
555. Split Concatenated Strings
Greedy
Array
String
Medium
556. Next Greater Element III
Math
Two Pointers
String
Medium
557. Reverse Words in a String III
Two Pointers
String
Easy
558. Logical OR of Two Binary Grids Represented as Quad-Trees
Tree
Divide and Conquer
Medium
559. Maximum Depth of N-ary Tree
Tree
Depth-First Search
Breadth-First Search
Easy
560. Subarray Sum Equals K
Array
Hash Table
Prefix Sum
Medium
561. Array Partition
Greedy
Array
Counting Sort
Sorting
Easy
562. Longest Line of Consecutive One in Matrix
Array
Dynamic Programming
Matrix
Medium
563. Binary Tree Tilt
Tree
Depth-First Search
Binary Tree
Easy
564. Find the Closest Palindrome
Math
String
Hard
565. Array Nesting
Depth-First Search
Array
Medium
566. Reshape the Matrix
Array
Matrix
Simulation
Easy
567. Permutation in String
Hash Table
Two Pointers
String
Sliding Window
Medium
568. Maximum Vacation Days
Array
Dynamic Programming
Matrix
Hard
572. Subtree of Another Tree
Tree
Depth-First Search
Binary Tree
String Matching
Hash Function
Easy
573. Squirrel Simulation
Array
Math
Medium
575. Distribute Candies
Array
Hash Table
Easy
576. Out of Boundary Paths
Dynamic Programming
Medium
581. Shortest Unsorted Continuous Subarray
Stack
Greedy
Array
Two Pointers
Sorting
Monotonic Stack
Medium
582. Kill Process
Tree
Depth-First Search
Breadth-First Search
Array
Hash Table
Medium
583. Delete Operation for Two Strings
String
Dynamic Programming
Medium
587. Erect the Fence
Geometry
Array
Math
Hard
588. Design In-Memory File System
Design
Trie
Hash Table
String
Sorting
Hard
589. N-ary Tree Preorder Traversal
Stack
Tree
Depth-First Search
Easy
590. N-ary Tree Postorder Traversal
Stack
Tree
Depth-First Search
Easy
591. Tag Validator
Stack
String
Hard
592. Fraction Addition and Subtraction
Math
String
Simulation
Medium
593. Valid Square
Geometry
Math
Medium
594. Longest Harmonious Subsequence
Array
Hash Table
Counting
Sorting
Sliding Window
Easy
598. Range Addition II
Array
Math
Easy
599. Minimum Index Sum of Two Lists
Array
Hash Table
String
Easy
600. Non-negative Integers without Consecutive Ones
Dynamic Programming
Hard
604. Design Compressed String Iterator
Design
Array
String
Iterator
Easy
605. Can Place Flowers
Greedy
Array
Easy
606. Construct String from Binary Tree
Tree
Depth-First Search
String
Binary Tree
Medium
609. Find Duplicate File in System
Array
Hash Table
String
Medium
611. Valid Triangle Number
Greedy
Array
Two Pointers
Binary Search
Sorting
Medium
616. Add Bold Tag in String
Trie
Array
Hash Table
String
String Matching
Medium
617. Merge Two Binary Trees
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
621. Task Scheduler
Greedy
Array
Hash Table
Counting
Sorting
Heap (Priority Queue)
Medium
622. Design Circular Queue
Design
Queue
Array
Linked List
Medium
623. Add One Row to Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
624. Maximum Distance in Arrays
Greedy
Array
Medium
625. Minimum Factorization
Greedy
Math
Medium
628. Maximum Product of Three Numbers
Array
Math
Sorting
Easy
629. K Inverse Pairs Array
Dynamic Programming
Hard
630. Course Schedule III
Greedy
Array
Sorting
Heap (Priority Queue)
Hard
631. Design Excel Sum Formula
Graph
Design
Topological Sort
Array
Hash Table
String
Matrix
Hard
632. Smallest Range Covering Elements from K Lists
Greedy
Array
Hash Table
Sorting
Sliding Window
Heap (Priority Queue)
Hard
633. Sum of Square Numbers
Math
Two Pointers
Binary Search
Medium
634. Find the Derangement of An Array
Math
Dynamic Programming
Combinatorics
Medium
635. Design Log Storage System
Design
Hash Table
String
Ordered Set
Medium
636. Exclusive Time of Functions
Stack
Array
Medium
637. Average of Levels in Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
638. Shopping Offers
Bit Manipulation
Memoization
Array
Dynamic Programming
Backtracking
Bitmask
Medium
639. Decode Ways II
String
Dynamic Programming
Hard
640. Solve the Equation
Math
String
Simulation
Medium
641. Design Circular Deque
Design
Queue
Array
Linked List
Medium
642. Design Search Autocomplete System
Depth-First Search
Design
Trie
String
Data Stream
Sorting
Heap (Priority Queue)
Hard
643. Maximum Average Subarray I
Array
Sliding Window
Easy
644. Maximum Average Subarray II
Array
Binary Search
Prefix Sum
Hard
645. Set Mismatch
Bit Manipulation
Array
Hash Table
Sorting
Easy
646. Maximum Length of Pair Chain
Greedy
Array
Dynamic Programming
Sorting
Medium
647. Palindromic Substrings
Two Pointers
String
Dynamic Programming
Medium
648. Replace Words
Trie
Array
Hash Table
String
Medium
649. Dota2 Senate
Greedy
Queue
String
Medium
650. 2 Keys Keyboard
Math
Dynamic Programming
Medium
651. 4 Keys Keyboard
Math
Dynamic Programming
Medium
652. Find Duplicate Subtrees
Tree
Depth-First Search
Hash Table
Binary Tree
Medium
653. Two Sum IV - Input is a BST
Tree
Depth-First Search
Breadth-First Search
Binary Search Tree
Hash Table
Two Pointers
Binary Tree
Easy
654. Maximum Binary Tree
Stack
Tree
Array
Divide and Conquer
Binary Tree
Monotonic Stack
Medium
655. Print Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
656. Coin Path
Array
Dynamic Programming
Hard
657. Robot Return to Origin
String
Simulation
Easy
658. Find K Closest Elements
Array
Two Pointers
Binary Search
Sorting
Sliding Window
Heap (Priority Queue)
Medium
659. Split Array into Consecutive Subsequences
Greedy
Array
Hash Table
Heap (Priority Queue)
Medium
660. Remove 9
Math
Hard
661. Image Smoother
Array
Matrix
Easy
662. Maximum Width of Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
663. Equal Tree Partition
Tree
Depth-First Search
Binary Tree
Medium
664. Strange Printer
String
Dynamic Programming
Hard
665. Non-decreasing Array
Array
Medium
666. Path Sum IV
Tree
Depth-First Search
Array
Hash Table
Binary Tree
Medium
667. Beautiful Arrangement II
Array
Math
Medium
668. Kth Smallest Number in Multiplication Table
Math
Binary Search
Hard
669. Trim a Binary Search Tree
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Medium
670. Maximum Swap
Greedy
Math
Medium
671. Second Minimum Node In a Binary Tree
Tree
Depth-First Search
Binary Tree
Easy
672. Bulb Switcher II
Bit Manipulation
Depth-First Search
Breadth-First Search
Math
Medium
673. Number of Longest Increasing Subsequence
Binary Indexed Tree
Segment Tree
Array
Dynamic Programming
Medium
674. Longest Continuous Increasing Subsequence
Array
Easy
675. Cut Off Trees for Golf Event
Breadth-First Search
Array
Matrix
Heap (Priority Queue)
Hard
676. Implement Magic Dictionary
Depth-First Search
Design
Trie
Hash Table
String
Medium
677. Map Sum Pairs
Design
Trie
Hash Table
String
Medium
678. Valid Parenthesis String
Stack
Greedy
String
Dynamic Programming
Medium
679. 24 Game
Array
Math
Backtracking
Hard
680. Valid Palindrome II
Greedy
Two Pointers
String
Easy
681. Next Closest Time
Hash Table
String
Backtracking
Enumeration
Medium
682. Baseball Game
Stack
Array
Simulation
Easy
683. K Empty Slots
Binary Indexed Tree
Segment Tree
Queue
Array
Ordered Set
Sliding Window
Monotonic Queue
Heap (Priority Queue)
Hard
684. Redundant Connection
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
685. Redundant Connection II
Depth-First Search
Breadth-First Search
Union Find
Graph
Hard
686. Repeated String Match
String
String Matching
Medium
687. Longest Univalue Path
Tree
Depth-First Search
Binary Tree
Medium
688. Knight Probability in Chessboard
Dynamic Programming
Medium
689. Maximum Sum of 3 Non-Overlapping Subarrays
Array
Dynamic Programming
Prefix Sum
Sliding Window
Hard
690. Employee Importance
Tree
Depth-First Search
Breadth-First Search
Array
Hash Table
Medium
691. Stickers to Spell Word
Bit Manipulation
Memoization
Array
Hash Table
String
Dynamic Programming
Backtracking
Bitmask
Hard
692. Top K Frequent Words
Trie
Array
Hash Table
String
Bucket Sort
Counting
Sorting
Heap (Priority Queue)
Medium
693. Binary Number with Alternating Bits
Bit Manipulation
Easy
694. Number of Distinct Islands
Depth-First Search
Breadth-First Search
Union Find
Hash Table
Hash Function
Medium
695. Max Area of Island
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
696. Count Binary Substrings
Two Pointers
String
Easy
697. Degree of an Array
Array
Hash Table
Easy
698. Partition to K Equal Sum Subsets
Bit Manipulation
Memoization
Array
Dynamic Programming
Backtracking
Bitmask
Medium
699. Falling Squares
Segment Tree
Array
Ordered Set
Hard
700. Search in a Binary Search Tree
Tree
Binary Search Tree
Binary Tree
Easy
701. Insert into a Binary Search Tree
Tree
Binary Search Tree
Binary Tree
Medium
702. Search in a Sorted Array of Unknown Size
Array
Binary Search
Interactive
Medium
703. Kth Largest Element in a Stream
Tree
Design
Binary Search Tree
Binary Tree
Data Stream
Heap (Priority Queue)
Easy
704. Binary Search
Array
Binary Search
Easy
705. Design HashSet
Design
Array
Hash Table
Linked List
Hash Function
Easy
706. Design HashMap
Design
Array
Hash Table
Linked List
Hash Function
Easy
707. Design Linked List
Design
Linked List
Medium
708. Insert into a Sorted Circular Linked List
Linked List
Medium
709. To Lower Case
String
Easy
710. Random Pick with Blacklist
Array
Hash Table
Math
Binary Search
Sorting
Randomized
Hard
711. Number of Distinct Islands II
Depth-First Search
Breadth-First Search
Union Find
Hash Table
Hash Function
Hard
712. Minimum ASCII Delete Sum for Two Strings
String
Dynamic Programming
Medium
713. Subarray Product Less Than K
Array
Sliding Window
Medium
714. Best Time to Buy and Sell Stock with Transaction Fee
Greedy
Array
Dynamic Programming
Medium
715. Range Module
Design
Segment Tree
Ordered Set
Hard
716. Max Stack
Stack
Design
Linked List
Doubly-Linked List
Ordered Set
Hard
717. 1-bit and 2-bit Characters
Array
Easy
718. Maximum Length of Repeated Subarray
Array
Binary Search
Dynamic Programming
Sliding Window
Hash Function
Rolling Hash
Medium
719. Find K-th Smallest Pair Distance
Array
Two Pointers
Binary Search
Sorting
Hard
720. Longest Word in Dictionary
Trie
Array
Hash Table
String
Sorting
Medium
721. Accounts Merge
Depth-First Search
Breadth-First Search
Union Find
Array
Hash Table
String
Sorting
Medium
722. Remove Comments
Array
String
Medium
723. Candy Crush
Array
Two Pointers
Matrix
Simulation
Medium
724. Find Pivot Index
Array
Prefix Sum
Easy
725. Split Linked List in Parts
Linked List
Medium
726. Number of Atoms
Stack
Hash Table
String
Sorting
Hard
727. Minimum Window Subsequence
String
Dynamic Programming
Sliding Window
Hard
728. Self Dividing Numbers
Math
Easy
729. My Calendar I
Design
Segment Tree
Array
Binary Search
Ordered Set
Medium
730. Count Different Palindromic Subsequences
String
Dynamic Programming
Hard
731. My Calendar II
Design
Segment Tree
Array
Binary Search
Ordered Set
Prefix Sum
Medium
732. My Calendar III
Design
Segment Tree
Binary Search
Ordered Set
Prefix Sum
Hard
733. Flood Fill
Depth-First Search
Breadth-First Search
Array
Matrix
Easy
734. Sentence Similarity
Array
Hash Table
String
Easy
735. Asteroid Collision
Stack
Array
Simulation
Medium
736. Parse Lisp Expression
Stack
Recursion
Hash Table
String
Hard
737. Sentence Similarity II
Depth-First Search
Breadth-First Search
Union Find
Array
Hash Table
String
Medium
738. Monotone Increasing Digits
Greedy
Math
Medium
739. Daily Temperatures
Stack
Array
Monotonic Stack
Medium
740. Delete and Earn
Array
Hash Table
Dynamic Programming
Medium
741. Cherry Pickup
Array
Dynamic Programming
Matrix
Hard
742. Closest Leaf in a Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
743. Network Delay Time
Depth-First Search
Breadth-First Search
Graph
Shortest Path
Heap (Priority Queue)
Medium
744. Find Smallest Letter Greater Than Target
Array
Binary Search
Easy
745. Prefix and Suffix Search
Design
Trie
Array
Hash Table
String
Hard
746. Min Cost Climbing Stairs
Array
Dynamic Programming
Easy
747. Largest Number At Least Twice of Others
Array
Sorting
Easy
748. Shortest Completing Word
Array
Hash Table
String
Easy
749. Contain Virus
Depth-First Search
Breadth-First Search
Array
Matrix
Simulation
Hard
750. Number Of Corner Rectangles
Array
Math
Dynamic Programming
Matrix
Medium
751. IP to CIDR
Bit Manipulation
String
Medium
752. Open the Lock
Breadth-First Search
Array
Hash Table
String
Medium
753. Cracking the Safe
Depth-First Search
Graph
Eulerian Circuit
Hard
754. Reach a Number
Math
Binary Search
Medium
755. Pour Water
Array
Simulation
Medium
756. Pyramid Transition Matrix
Bit Manipulation
Depth-First Search
Breadth-First Search
Medium
757. Set Intersection Size At Least Two
Greedy
Array
Sorting
Hard
758. Bold Words in String
Trie
Array
Hash Table
String
String Matching
Medium
759. Employee Free Time
Array
Sorting
Line Sweep
Heap (Priority Queue)
Hard
760. Find Anagram Mappings
Array
Hash Table
Easy
761. Special Binary String
Recursion
String
Hard
762. Prime Number of Set Bits in Binary Representation
Bit Manipulation
Math
Easy
763. Partition Labels
Greedy
Hash Table
Two Pointers
String
Medium
764. Largest Plus Sign
Array
Dynamic Programming
Medium
765. Couples Holding Hands
Greedy
Depth-First Search
Breadth-First Search
Union Find
Graph
Hard
766. Toeplitz Matrix
Array
Matrix
Easy
767. Reorganize String
Greedy
Hash Table
String
Counting
Sorting
Heap (Priority Queue)
Medium
768. Max Chunks To Make Sorted II
Stack
Greedy
Array
Sorting
Monotonic Stack
Hard
769. Max Chunks To Make Sorted
Stack
Greedy
Array
Sorting
Monotonic Stack
Medium
770. Basic Calculator IV
Stack
Recursion
Hash Table
Math
String
Hard
771. Jewels and Stones
Hash Table
String
Easy
772. Basic Calculator III
Stack
Recursion
Math
String
Hard
773. Sliding Puzzle
Breadth-First Search
Memoization
Array
Dynamic Programming
Backtracking
Matrix
Hard
774. Minimize Max Distance to Gas Station
Array
Binary Search
Hard
775. Global and Local Inversions
Array
Math
Medium
776. Split BST
Tree
Binary Search Tree
Recursion
Binary Tree
Medium
777. Swap Adjacent in LR String
Two Pointers
String
Medium
778. Swim in Rising Water
Depth-First Search
Breadth-First Search
Union Find
Array
Binary Search
Matrix
Heap (Priority Queue)
Hard
779. K-th Symbol in Grammar
Bit Manipulation
Recursion
Math
Medium
780. Reaching Points
Math
Hard
781. Rabbits in Forest
Greedy
Array
Hash Table
Math
Medium
782. Transform to Chessboard
Bit Manipulation
Array
Math
Matrix
Hard
783. Minimum Distance Between BST Nodes
Tree
Depth-First Search
Breadth-First Search
Binary Search Tree
Binary Tree
Easy
784. Letter Case Permutation
Bit Manipulation
String
Backtracking
Medium
785. Is Graph Bipartite
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
786. K-th Smallest Prime Fraction
Array
Two Pointers
Binary Search
Sorting
Heap (Priority Queue)
Medium
787. Cheapest Flights Within K Stops
Depth-First Search
Breadth-First Search
Graph
Dynamic Programming
Shortest Path
Heap (Priority Queue)
Medium
788. Rotated Digits
Math
Dynamic Programming
Medium
789. Escape The Ghosts
Array
Math
Medium
790. Domino and Tromino Tiling
Dynamic Programming
Medium
791. Custom Sort String
Hash Table
String
Sorting
Medium
792. Number of Matching Subsequences
Trie
Array
Hash Table
String
Binary Search
Dynamic Programming
Sorting
Medium
793. Preimage Size of Factorial Zeroes Function
Math
Binary Search
Hard
794. Valid Tic-Tac-Toe State
Array
Matrix
Medium
795. Number of Subarrays with Bounded Maximum
Array
Two Pointers
Medium
796. Rotate String
String
String Matching
Easy
797. All Paths From Source to Target
Depth-First Search
Breadth-First Search
Graph
Backtracking
Medium
798. Smallest Rotation with Highest Score
Array
Prefix Sum
Hard
799. Champagne Tower
Dynamic Programming
Medium
800. Similar RGB Color
Math
String
Enumeration
Easy
801. Minimum Swaps To Make Sequences Increasing
Array
Dynamic Programming
Hard
802. Find Eventual Safe States
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Medium
803. Bricks Falling When Hit
Union Find
Array
Matrix
Hard
804. Unique Morse Code Words
Array
Hash Table
String
Easy
805. Split Array With Same Average
Bit Manipulation
Array
Math
Dynamic Programming
Bitmask
Hard
806. Number of Lines To Write String
Array
String
Easy
807. Max Increase to Keep City Skyline
Greedy
Array
Matrix
Medium
808. Soup Servings
Math
Dynamic Programming
Probability and Statistics
Medium
809. Expressive Words
Array
Two Pointers
String
Medium
810. Chalkboard XOR Game
Bit Manipulation
Brainteaser
Array
Math
Game Theory
Hard
811. Subdomain Visit Count
Array
Hash Table
String
Counting
Medium
812. Largest Triangle Area
Geometry
Array
Math
Easy
813. Largest Sum of Averages
Array
Dynamic Programming
Prefix Sum
Medium
814. Binary Tree Pruning
Tree
Depth-First Search
Binary Tree
Medium
815. Bus Routes
Breadth-First Search
Array
Hash Table
Hard
816. Ambiguous Coordinates
String
Backtracking
Enumeration
Medium
817. Linked List Components
Array
Hash Table
Linked List
Medium
818. Race Car
Dynamic Programming
Hard
819. Most Common Word
Array
Hash Table
String
Counting
Easy
820. Short Encoding of Words
Trie
Array
Hash Table
String
Medium
821. Shortest Distance to a Character
Array
Two Pointers
String
Easy
822. Card Flipping Game
Array
Hash Table
Medium
823. Binary Trees With Factors
Array
Hash Table
Dynamic Programming
Sorting
Medium
824. Goat Latin
String
Easy
825. Friends Of Appropriate Ages
Array
Two Pointers
Binary Search
Sorting
Medium
826. Most Profit Assigning Work
Greedy
Array
Two Pointers
Binary Search
Sorting
Medium
827. Making A Large Island
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Hard
828. Count Unique Characters of All Substrings of a Given String
Hash Table
String
Dynamic Programming
Hard
829. Consecutive Numbers Sum
Math
Enumeration
Hard
830. Positions of Large Groups
String
Easy
831. Masking Personal Information
String
Medium
832. Flipping an Image
Bit Manipulation
Array
Two Pointers
Matrix
Simulation
Easy
833. Find And Replace in String
Array
Hash Table
String
Sorting
Medium
834. Sum of Distances in Tree
Tree
Depth-First Search
Graph
Dynamic Programming
Hard
835. Image Overlap
Array
Matrix
Medium
836. Rectangle Overlap
Geometry
Math
Easy
837. New 21 Game
Math
Dynamic Programming
Sliding Window
Probability and Statistics
Medium
838. Push Dominoes
Two Pointers
String
Dynamic Programming
Medium
839. Similar String Groups
Depth-First Search
Breadth-First Search
Union Find
Array
Hash Table
String
Hard
840. Magic Squares In Grid
Array
Hash Table
Math
Matrix
Medium
841. Keys and Rooms
Depth-First Search
Breadth-First Search
Graph
Medium
842. Split Array into Fibonacci Sequence
String
Backtracking
Medium
843. Guess the Word
Array
Math
String
Game Theory
Interactive
Hard
844. Backspace String Compare
Stack
Two Pointers
String
Simulation
Easy
845. Longest Mountain in Array
Array
Two Pointers
Dynamic Programming
Enumeration
Medium
846. Hand of Straights
Greedy
Array
Hash Table
Sorting
Medium
847. Shortest Path Visiting All Nodes
Bit Manipulation
Breadth-First Search
Graph
Dynamic Programming
Bitmask
Hard
848. Shifting Letters
Array
String
Prefix Sum
Medium
849. Maximize Distance to Closest Person
Array
Medium
850. Rectangle Area II
Segment Tree
Array
Ordered Set
Line Sweep
Hard
851. Loud and Rich
Depth-First Search
Graph
Topological Sort
Array
Medium
852. Peak Index in a Mountain Array
Array
Binary Search
Medium
853. Car Fleet
Stack
Array
Sorting
Monotonic Stack
Medium
854. K-Similar Strings
Breadth-First Search
Hash Table
String
Hard
855. Exam Room
Design
Ordered Set
Heap (Priority Queue)
Medium
856. Score of Parentheses
Stack
String
Medium
857. Minimum Cost to Hire K Workers
Greedy
Array
Sorting
Heap (Priority Queue)
Hard
858. Mirror Reflection
Geometry
Math
Number Theory
Medium
859. Buddy Strings
Hash Table
String
Easy
860. Lemonade Change
Greedy
Array
Easy
861. Score After Flipping Matrix
Greedy
Bit Manipulation
Array
Matrix
Medium
862. Shortest Subarray with Sum at Least K
Queue
Array
Binary Search
Prefix Sum
Sliding Window
Monotonic Queue
Heap (Priority Queue)
Hard
863. All Nodes Distance K in Binary Tree
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Medium
864. Shortest Path to Get All Keys
Bit Manipulation
Breadth-First Search
Array
Matrix
Hard
865. Smallest Subtree with all the Deepest Nodes
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Medium
866. Prime Palindrome
Math
Medium
867. Transpose Matrix
Array
Matrix
Simulation
Easy
868. Binary Gap
Bit Manipulation
Easy
869. Reordered Power of 2
Hash Table
Math
Counting
Enumeration
Sorting
Medium
870. Advantage Shuffle
Greedy
Array
Two Pointers
Sorting
Medium
871. Minimum Number of Refueling Stops
Greedy
Array
Dynamic Programming
Heap (Priority Queue)
Hard
872. Leaf-Similar Trees
Tree
Depth-First Search
Binary Tree
Easy
873. Length of Longest Fibonacci Subsequence
Array
Hash Table
Dynamic Programming
Medium
874. Walking Robot Simulation
Array
Hash Table
Simulation
Medium
875. Koko Eating Bananas
Array
Binary Search
Medium
876. Middle of the Linked List
Linked List
Two Pointers
Easy
877. Stone Game
Array
Math
Dynamic Programming
Game Theory
Medium
878. Nth Magical Number
Math
Binary Search
Hard
879. Profitable Schemes
Array
Dynamic Programming
Hard
880. Decoded String at Index
Stack
String
Medium
881. Boats to Save People
Greedy
Array
Two Pointers
Sorting
Medium
882. Reachable Nodes In Subdivided Graph
Graph
Shortest Path
Heap (Priority Queue)
Hard
883. Projection Area of 3D Shapes
Geometry
Array
Math
Matrix
Easy
884. Uncommon Words from Two Sentences
Hash Table
String
Counting
Easy
885. Spiral Matrix III
Array
Matrix
Simulation
Medium
886. Possible Bipartition
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
887. Super Egg Drop
Math
Binary Search
Dynamic Programming
Hard
888. Fair Candy Swap
Array
Hash Table
Binary Search
Sorting
Easy
889. Construct Binary Tree from Preorder and Postorder Traversal
Tree
Array
Hash Table
Divide and Conquer
Binary Tree
Medium
890. Find and Replace Pattern
Array
Hash Table
String
Medium
891. Sum of Subsequence Widths
Array
Math
Sorting
Hard
892. Surface Area of 3D Shapes
Geometry
Array
Math
Matrix
Easy
893. Groups of Special-Equivalent Strings
Array
Hash Table
String
Sorting
Medium
894. All Possible Full Binary Trees
Tree
Recursion
Memoization
Dynamic Programming
Binary Tree
Medium
895. Maximum Frequency Stack
Stack
Design
Hash Table
Ordered Set
Hard
896. Monotonic Array
Array
Easy
897. Increasing Order Search Tree
Stack
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Easy
898. Bitwise ORs of Subarrays
Bit Manipulation
Array
Dynamic Programming
Medium
899. Orderly Queue
Math
String
Sorting
Hard
900. RLE Iterator
Design
Array
Counting
Iterator
Medium
901. Online Stock Span
Stack
Design
Data Stream
Monotonic Stack
Medium
902. Numbers At Most N Given Digit Set
Array
Math
String
Binary Search
Dynamic Programming
Hard
903. Valid Permutations for DI Sequence
String
Dynamic Programming
Prefix Sum
Hard
904. Fruit Into Baskets
Array
Hash Table
Sliding Window
Medium
905. Sort Array By Parity
Array
Two Pointers
Sorting
Easy
906. Super Palindromes
Math
String
Enumeration
Hard
907. Sum of Subarray Minimums
Stack
Array
Dynamic Programming
Monotonic Stack
Medium
908. Smallest Range I
Array
Math
Easy
909. Snakes and Ladders
Breadth-First Search
Array
Matrix
Medium
910. Smallest Range II
Greedy
Array
Math
Sorting
Medium
911. Online Election
Design
Array
Hash Table
Binary Search
Medium
912. Sort an Array
Array
Divide and Conquer
Bucket Sort
Counting Sort
Radix Sort
Sorting
Heap (Priority Queue)
Merge Sort
Medium
913. Cat and Mouse
Graph
Topological Sort
Memoization
Math
Dynamic Programming
Game Theory
Hard
914. X of a Kind in a Deck of Cards
Array
Hash Table
Math
Counting
Number Theory
Easy
915. Partition Array into Disjoint Intervals
Array
Medium
916. Word Subsets
Array
Hash Table
String
Medium
917. Reverse Only Letters
Two Pointers
String
Easy
918. Maximum Sum Circular Subarray
Queue
Array
Divide and Conquer
Dynamic Programming
Monotonic Queue
Medium
919. Complete Binary Tree Inserter
Tree
Breadth-First Search
Design
Binary Tree
Medium
920. Number of Music Playlists
Math
Dynamic Programming
Combinatorics
Hard
921. Minimum Add to Make Parentheses Valid
Stack
Greedy
String
Medium
922. Sort Array By Parity II
Array
Two Pointers
Sorting
Easy
923. 3Sum With Multiplicity
Array
Hash Table
Two Pointers
Counting
Sorting
Medium
924. Minimize Malware Spread
Depth-First Search
Breadth-First Search
Union Find
Graph
Array
Hash Table
Hard
925. Long Pressed Name
Two Pointers
String
Easy
926. Flip String to Monotone Increasing
String
Dynamic Programming
Medium
927. Three Equal Parts
Array
Math
Hard
928. Minimize Malware Spread II
Depth-First Search
Breadth-First Search
Union Find
Graph
Array
Hash Table
Hard
929. Unique Email Addresses
Array
Hash Table
String
Easy
930. Binary Subarrays With Sum
Array
Hash Table
Prefix Sum
Sliding Window
Medium
931. Minimum Falling Path Sum
Array
Dynamic Programming
Matrix
Medium
932. Beautiful Array
Array
Math
Divide and Conquer
Medium
933. Number of Recent Calls
Design
Queue
Data Stream
Easy
934. Shortest Bridge
Depth-First Search
Breadth-First Search
Array
Matrix
Medium
935. Knight Dialer
Dynamic Programming
Medium
936. Stamping The Sequence
Stack
Greedy
Queue
String
Hard
937. Reorder Data in Log Files
Array
String
Sorting
Medium
938. Range Sum of BST
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Easy
939. Minimum Area Rectangle
Geometry
Array
Hash Table
Math
Sorting
Medium
940. Distinct Subsequences II
String
Dynamic Programming
Hard
941. Valid Mountain Array
Array
Easy
942. DI String Match
Greedy
Array
Two Pointers
String
Easy
943. Find the Shortest Superstring
Bit Manipulation
Array
String
Dynamic Programming
Bitmask
Hard
944. Delete Columns to Make Sorted
Array
String
Easy
945. Minimum Increment to Make Array Unique
Greedy
Array
Counting
Sorting
Medium
946. Validate Stack Sequences
Stack
Array
Simulation
Medium
947. Most Stones Removed with Same Row or Column
Depth-First Search
Union Find
Graph
Hash Table
Medium
948. Bag of Tokens
Greedy
Array
Two Pointers
Sorting
Medium
949. Largest Time for Given Digits
Array
String
Backtracking
Enumeration
Medium
950. Reveal Cards In Increasing Order
Queue
Array
Sorting
Simulation
Medium
951. Flip Equivalent Binary Trees
Tree
Depth-First Search
Binary Tree
Medium
952. Largest Component Size by Common Factor
Union Find
Array
Hash Table
Math
Number Theory
Hard
953. Verifying an Alien Dictionary
Array
Hash Table
String
Easy
954. Array of Doubled Pairs
Greedy
Array
Hash Table
Sorting
Medium
955. Delete Columns to Make Sorted II
Greedy
Array
String
Medium
956. Tallest Billboard
Array
Dynamic Programming
Hard
957. Prison Cells After N Days
Bit Manipulation
Array
Hash Table
Math
Medium
958. Check Completeness of a Binary Tree
Tree
Breadth-First Search
Binary Tree
Medium
959. Regions Cut By Slashes
Depth-First Search
Breadth-First Search
Union Find
Array
Hash Table
Matrix
Medium
960. Delete Columns to Make Sorted III
Array
String
Dynamic Programming
Hard
961. N-Repeated Element in Size 2N Array
Array
Hash Table
Easy
962. Maximum Width Ramp
Stack
Array
Two Pointers
Monotonic Stack
Medium
963. Minimum Area Rectangle II
Geometry
Array
Hash Table
Math
Medium
964. Least Operators to Express Number
Memoization
Math
Dynamic Programming
Hard
965. Univalued Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
966. Vowel Spellchecker
Array
Hash Table
String
Medium
967. Numbers With Same Consecutive Differences
Breadth-First Search
Backtracking
Medium
968. Binary Tree Cameras
Tree
Depth-First Search
Dynamic Programming
Binary Tree
Hard
969. Pancake Sorting
Greedy
Array
Two Pointers
Sorting
Medium
970. Powerful Integers
Hash Table
Math
Enumeration
Medium
971. Flip Binary Tree To Match Preorder Traversal
Tree
Depth-First Search
Binary Tree
Medium
972. Equal Rational Numbers
Math
String
Hard
973. K Closest Points to Origin
Geometry
Array
Math
Divide and Conquer
Quickselect
Sorting
Heap (Priority Queue)
Medium
974. Subarray Sums Divisible by K
Array
Hash Table
Prefix Sum
Medium
975. Odd Even Jump
Stack
Array
Dynamic Programming
Ordered Set
Sorting
Monotonic Stack
Hard
976. Largest Perimeter Triangle
Greedy
Array
Math
Sorting
Easy
977. Squares of a Sorted Array
Array
Two Pointers
Sorting
Easy
978. Longest Turbulent Subarray
Array
Dynamic Programming
Sliding Window
Medium
979. Distribute Coins in Binary Tree
Tree
Depth-First Search
Binary Tree
Medium
980. Unique Paths III
Bit Manipulation
Array
Backtracking
Matrix
Hard
981. Time Based Key-Value Store
Design
Hash Table
String
Binary Search
Medium
982. Triples with Bitwise AND Equal To Zero
Bit Manipulation
Array
Hash Table
Hard
983. Minimum Cost For Tickets
Array
Dynamic Programming
Medium
984. String Without AAA or BBB
Greedy
String
Medium
985. Sum of Even Numbers After Queries
Array
Simulation
Medium
986. Interval List Intersections
Array
Two Pointers
Line Sweep
Medium
987. Vertical Order Traversal of a Binary Tree
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Sorting
Hard
988. Smallest String Starting From Leaf
Tree
Depth-First Search
String
Backtracking
Binary Tree
Medium
989. Add to Array-Form of Integer
Array
Math
Easy
990. Satisfiability of Equality Equations
Union Find
Graph
Array
String
Medium
991. Broken Calculator
Greedy
Math
Medium
992. Subarrays with K Different Integers
Array
Hash Table
Counting
Sliding Window
Hard
993. Cousins in Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
994. Rotting Oranges
Breadth-First Search
Array
Matrix
Medium
995. Minimum Number of K Consecutive Bit Flips
Bit Manipulation
Queue
Array
Prefix Sum
Sliding Window
Hard
996. Number of Squareful Arrays
Bit Manipulation
Array
Hash Table
Math
Dynamic Programming
Backtracking
Bitmask
Hard
997. Find the Town Judge
Graph
Array
Hash Table
Easy
998. Maximum Binary Tree II
Tree
Binary Tree
Medium
999. Available Captures for Rook
Array
Matrix
Simulation
Easy
1000. Minimum Cost to Merge Stones
Array
Dynamic Programming
Prefix Sum
Hard
1001. Grid Illumination
Array
Hash Table
Hard
1002. Find Common Characters
Array
Hash Table
String
Easy
1003. Check If Word Is Valid After Substitutions
Stack
String
Medium
1004. Max Consecutive Ones III
Array
Binary Search
Prefix Sum
Sliding Window
Medium
1005. Maximize Sum Of Array After K Negations
Greedy
Array
Sorting
Easy
1006. Clumsy Factorial
Stack
Math
Simulation
Medium
1007. Minimum Domino Rotations For Equal Row
Greedy
Array
Medium
1008. Construct Binary Search Tree from Preorder Traversal
Stack
Tree
Binary Search Tree
Array
Binary Tree
Monotonic Stack
Medium
1009. Complement of Base 10 Integer
Bit Manipulation
Easy
1010. Pairs of Songs With Total Durations Divisible by 60
Array
Hash Table
Counting
Medium
1011. Capacity To Ship Packages Within D Days
Array
Binary Search
Medium
1012. Numbers With Repeated Digits
Math
Dynamic Programming
Hard
1013. Partition Array Into Three Parts With Equal Sum
Greedy
Array
Easy
1014. Best Sightseeing Pair
Array
Dynamic Programming
Medium
1015. Smallest Integer Divisible by K
Hash Table
Math
Medium
1016. Binary String With Substrings Representing 1 To N
Bit Manipulation
Hash Table
String
Sliding Window
Medium
1017. Convert to Base -2
Math
Medium
1018. Binary Prefix Divisible By 5
Bit Manipulation
Array
Easy
1019. Next Greater Node In Linked List
Stack
Array
Linked List
Monotonic Stack
Medium
1020. Number of Enclaves
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
1021. Remove Outermost Parentheses
Stack
String
Easy
1022. Sum of Root To Leaf Binary Numbers
Tree
Depth-First Search
Binary Tree
Easy
1023. Camelcase Matching
Trie
Array
Two Pointers
String
String Matching
Medium
1024. Video Stitching
Greedy
Array
Dynamic Programming
Medium
1025. Divisor Game
Brainteaser
Math
Dynamic Programming
Game Theory
Easy
1026. Maximum Difference Between Node and Ancestor
Tree
Depth-First Search
Binary Tree
Medium
1027. Longest Arithmetic Subsequence
Array
Hash Table
Binary Search
Dynamic Programming
Medium
1028. Recover a Tree From Preorder Traversal
Tree
Depth-First Search
String
Binary Tree
Hard
1029. Two City Scheduling
Greedy
Array
Sorting
Medium
1030. Matrix Cells in Distance Order
Geometry
Array
Math
Matrix
Sorting
Easy
1031. Maximum Sum of Two Non-Overlapping Subarrays
Array
Dynamic Programming
Sliding Window
Medium
1032. Stream of Characters
Design
Trie
Array
String
Data Stream
Hard
1033. Moving Stones Until Consecutive
Brainteaser
Math
Medium
1034. Coloring A Border
Depth-First Search
Breadth-First Search
Array
Matrix
Medium
1035. Uncrossed Lines
Array
Dynamic Programming
Medium
1036. Escape a Large Maze
Depth-First Search
Breadth-First Search
Array
Hash Table
Hard
1037. Valid Boomerang
Geometry
Array
Math
Easy
1038. Binary Search Tree to Greater Sum Tree
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Medium
1039. Minimum Score Triangulation of Polygon
Array
Dynamic Programming
Medium
1040. Moving Stones Until Consecutive II
Array
Math
Sorting
Sliding Window
Medium
1041. Robot Bounded In Circle
Math
String
Simulation
Medium
1042. Flower Planting With No Adjacent
Depth-First Search
Breadth-First Search
Graph
Medium
1043. Partition Array for Maximum Sum
Array
Dynamic Programming
Medium
1044. Longest Duplicate Substring
String
Binary Search
Suffix Array
Sliding Window
Hash Function
Rolling Hash
Hard
1046. Last Stone Weight
Array
Heap (Priority Queue)
Easy
1047. Remove All Adjacent Duplicates In String
Stack
String
Easy
1048. Longest String Chain
Array
Hash Table
Two Pointers
String
Dynamic Programming
Sorting
Medium
1049. Last Stone Weight II
Array
Dynamic Programming
Medium
1051. Height Checker
Array
Counting Sort
Sorting
Easy
1052. Grumpy Bookstore Owner
Array
Sliding Window
Medium
1053. Previous Permutation With One Swap
Greedy
Array
Medium
1054. Distant Barcodes
Greedy
Array
Hash Table
Counting
Sorting
Heap (Priority Queue)
Medium
1055. Shortest Way to Form String
Greedy
Two Pointers
String
Binary Search
Medium
1056. Confusing Number
Math
Easy
1057. Campus Bikes
Array
Sorting
Heap (Priority Queue)
Medium
1058. Minimize Rounding Error to Meet Target
Greedy
Array
Math
String
Sorting
Medium
1059. All Paths from Source Lead to Destination
Graph
Topological Sort
Medium
1060. Missing Element in Sorted Array
Array
Binary Search
Medium
1061. Lexicographically Smallest Equivalent String
Union Find
String
Medium
1062. Longest Repeating Substring
String
Binary Search
Dynamic Programming
Suffix Array
Hash Function
Rolling Hash
Medium
1063. Number of Valid Subarrays
Stack
Array
Monotonic Stack
Hard
1064. Fixed Point
Array
Binary Search
Easy
1065. Index Pairs of a String
Trie
Array
String
Sorting
Easy
1066. Campus Bikes II
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Medium
1067. Digit Count in Range
Math
Dynamic Programming
Hard
1071. Greatest Common Divisor of Strings
Math
String
Easy
1072. Flip Columns For Maximum Number of Equal Rows
Array
Hash Table
Matrix
Medium
1073. Adding Two Negabinary Numbers
Array
Math
Medium
1074. Number of Submatrices That Sum to Target
Array
Hash Table
Matrix
Prefix Sum
Hard
1078. Occurrences After Bigram
String
Easy
1079. Letter Tile Possibilities
Hash Table
String
Backtracking
Counting
Medium
1080. Insufficient Nodes in Root to Leaf Paths
Tree
Depth-First Search
Binary Tree
Medium
1081. Smallest Subsequence of Distinct Characters
Stack
Greedy
String
Monotonic Stack
Medium
1085. Sum of Digits in the Minimum Number
Array
Math
Easy
1086. High Five
Array
Hash Table
Sorting
Heap (Priority Queue)
Easy
1087. Brace Expansion
Breadth-First Search
String
Backtracking
Medium
1088. Confusing Number II
Math
Backtracking
Hard
1089. Duplicate Zeros
Array
Two Pointers
Easy
1090. Largest Values From Labels
Greedy
Array
Hash Table
Counting
Sorting
Medium
1091. Shortest Path in Binary Matrix
Breadth-First Search
Array
Matrix
Medium
1092. Shortest Common Supersequence
String
Dynamic Programming
Hard
1093. Statistics from a Large Sample
Array
Math
Probability and Statistics
Medium
1094. Car Pooling
Array
Prefix Sum
Sorting
Simulation
Heap (Priority Queue)
Medium
1095. Find in Mountain Array
Array
Binary Search
Interactive
Hard
1096. Brace Expansion II
Stack
Breadth-First Search
String
Backtracking
Hard
1099. Two Sum Less Than K
Array
Two Pointers
Binary Search
Sorting
Easy
1100. Find K-Length Substrings With No Repeated Characters
Hash Table
String
Sliding Window
Medium
1101. The Earliest Moment When Everyone Become Friends
Union Find
Array
Sorting
Medium
1102. Path With Maximum Minimum Value
Depth-First Search
Breadth-First Search
Union Find
Array
Binary Search
Matrix
Heap (Priority Queue)
Medium
1103. Distribute Candies to People
Math
Simulation
Easy
1104. Path In Zigzag Labelled Binary Tree
Tree
Math
Binary Tree
Medium
1105. Filling Bookcase Shelves
Array
Dynamic Programming
Medium
1106. Parsing A Boolean Expression
Stack
Recursion
String
Hard
1108. Defanging an IP Address
String
Easy
1109. Corporate Flight Bookings
Array
Prefix Sum
Medium
1110. Delete Nodes And Return Forest
Tree
Depth-First Search
Array
Hash Table
Binary Tree
Medium
1111. Maximum Nesting Depth of Two Valid Parentheses Strings
Stack
String
Medium
1114. Print in Order
Concurrency
Easy
1115. Print FooBar Alternately
Concurrency
Medium
1116. Print Zero Even Odd
Concurrency
Medium
1117. Building H2O
Concurrency
Medium
1118. Number of Days in a Month
Math
Easy
1119. Remove Vowels from a String
String
Easy
1120. Maximum Average Subtree
Tree
Depth-First Search
Binary Tree
Medium
1121. Divide Array Into Increasing Sequences
Array
Counting
Hard
1122. Relative Sort Array
Array
Hash Table
Counting Sort
Sorting
Easy
1123. Lowest Common Ancestor of Deepest Leaves
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Medium
1124. Longest Well-Performing Interval
Stack
Array
Hash Table
Prefix Sum
Monotonic Stack
Medium
1125. Smallest Sufficient Team
Bit Manipulation
Array
Dynamic Programming
Bitmask
Hard
1128. Number of Equivalent Domino Pairs
Array
Hash Table
Counting
Easy
1129. Shortest Path with Alternating Colors
Breadth-First Search
Graph
Medium
1130. Minimum Cost Tree From Leaf Values
Stack
Greedy
Array
Dynamic Programming
Monotonic Stack
Medium
1131. Maximum of Absolute Value Expression
Array
Math
Medium
1133. Largest Unique Number
Array
Hash Table
Sorting
Easy
1134. Armstrong Number
Math
Easy
1135. Connecting Cities With Minimum Cost
Union Find
Graph
Minimum Spanning Tree
Heap (Priority Queue)
Medium
1136. Parallel Courses
Graph
Topological Sort
Medium
1137. N-th Tribonacci Number
Memoization
Math
Dynamic Programming
Easy
1138. Alphabet Board Path
Hash Table
String
Medium
1139. Largest 1-Bordered Square
Array
Dynamic Programming
Matrix
Medium
1140. Stone Game II
Array
Math
Dynamic Programming
Game Theory
Prefix Sum
Medium
1143. Longest Common Subsequence
String
Dynamic Programming
Medium
1144. Decrease Elements To Make Array Zigzag
Greedy
Array
Medium
1145. Binary Tree Coloring Game
Tree
Depth-First Search
Binary Tree
Medium
1146. Snapshot Array
Design
Array
Hash Table
Binary Search
Medium
1147. Longest Chunked Palindrome Decomposition
Greedy
Two Pointers
String
Dynamic Programming
Hash Function
Rolling Hash
Hard
1150. Check If a Number Is Majority Element in a Sorted Array
Array
Binary Search
Easy
1151. Minimum Swaps to Group All 1's Together
Array
Sliding Window
Medium
1152. Analyze User Website Visit Pattern
Array
Hash Table
String
Sorting
Medium
1153. String Transforms Into Another String
Graph
Hash Table
String
Hard
1154. Day of the Year
Math
String
Easy
1155. Number of Dice Rolls With Target Sum
Dynamic Programming
Medium
1156. Swap For Longest Repeated Character Substring
Hash Table
String
Sliding Window
Medium
1157. Online Majority Element In Subarray
Design
Binary Indexed Tree
Segment Tree
Array
Binary Search
Hard
1160. Find Words That Can Be Formed by Characters
Array
Hash Table
String
Counting
Easy
1161. Maximum Level Sum of a Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
1162. As Far from Land as Possible
Breadth-First Search
Array
Dynamic Programming
Matrix
Medium
1163. Last Substring in Lexicographical Order
Two Pointers
String
Hard
1165. Single-Row Keyboard
Hash Table
String
Easy
1166. Design File System
Design
Trie
Hash Table
String
Medium
1167. Minimum Cost to Connect Sticks
Greedy
Array
Heap (Priority Queue)
Medium
1168. Optimize Water Distribution in a Village
Union Find
Graph
Minimum Spanning Tree
Heap (Priority Queue)
Hard
1169. Invalid Transactions
Array
Hash Table
String
Sorting
Medium
1170. Compare Strings by Frequency of the Smallest Character
Array
Hash Table
String
Binary Search
Sorting
Medium
1171. Remove Zero Sum Consecutive Nodes from Linked List
Hash Table
Linked List
Medium
1172. Dinner Plate Stacks
Stack
Design
Hash Table
Heap (Priority Queue)
Hard
1175. Prime Arrangements
Math
Easy
1176. Diet Plan Performance
Array
Sliding Window
Easy
1177. Can Make Palindrome from Substring
Bit Manipulation
Array
Hash Table
String
Prefix Sum
Medium
1178. Number of Valid Words for Each Puzzle
Bit Manipulation
Trie
Array
Hash Table
String
Hard
1180. Count Substrings with Only One Distinct Letter
Math
String
Easy
1181. Before and After Puzzle
Array
Hash Table
String
Sorting
Medium
1182. Shortest Distance to Target Color
Array
Binary Search
Dynamic Programming
Medium
1183. Maximum Number of Ones
Greedy
Math
Sorting
Heap (Priority Queue)
Hard
1184. Distance Between Bus Stops
Array
Easy
1185. Day of the Week
Math
Easy
1186. Maximum Subarray Sum with One Deletion
Array
Dynamic Programming
Medium
1187. Make Array Strictly Increasing
Array
Binary Search
Dynamic Programming
Sorting
Hard
1188. Design Bounded Blocking Queue
Concurrency
Medium
1189. Maximum Number of Balloons
Hash Table
String
Counting
Easy
1190. Reverse Substrings Between Each Pair of Parentheses
Stack
String
Medium
1191. K-Concatenation Maximum Sum
Array
Dynamic Programming
Medium
1192. Critical Connections in a Network
Depth-First Search
Graph
Biconnected Component
Hard
1195. Fizz Buzz Multithreaded
Concurrency
Medium
1196. How Many Apples Can You Put into the Basket
Greedy
Array
Sorting
Easy
1197. Minimum Knight Moves
Breadth-First Search
Medium
1198. Find Smallest Common Element in All Rows
Array
Hash Table
Binary Search
Counting
Matrix
Medium
1199. Minimum Time to Build Blocks
Greedy
Array
Math
Heap (Priority Queue)
Hard
1200. Minimum Absolute Difference
Array
Sorting
Easy
1201. Ugly Number III
Math
Binary Search
Combinatorics
Number Theory
Medium
1202. Smallest String With Swaps
Depth-First Search
Breadth-First Search
Union Find
Array
Hash Table
String
Sorting
Medium
1203. Sort Items by Groups Respecting Dependencies
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Hard
1206. Design Skiplist
Design
Linked List
Hard
1207. Unique Number of Occurrences
Array
Hash Table
Easy
1208. Get Equal Substrings Within Budget
String
Binary Search
Prefix Sum
Sliding Window
Medium
1209. Remove All Adjacent Duplicates in String II
Stack
String
Medium
1210. Minimum Moves to Reach Target with Rotations
Breadth-First Search
Array
Matrix
Hard
1213. Intersection of Three Sorted Arrays
Array
Hash Table
Binary Search
Counting
Easy
1214. Two Sum BSTs
Stack
Tree
Depth-First Search
Binary Search Tree
Two Pointers
Binary Search
Binary Tree
Medium
1215. Stepping Numbers
Breadth-First Search
Math
Backtracking
Medium
1216. Valid Palindrome III
String
Dynamic Programming
Hard
1217. Minimum Cost to Move Chips to The Same Position
Greedy
Array
Math
Easy
1218. Longest Arithmetic Subsequence of Given Difference
Array
Hash Table
Dynamic Programming
Medium
1219. Path with Maximum Gold
Array
Backtracking
Matrix
Medium
1220. Count Vowels Permutation
Dynamic Programming
Hard
1221. Split a String in Balanced Strings
Greedy
String
Counting
Easy
1222. Queens That Can Attack the King
Array
Matrix
Simulation
Medium
1223. Dice Roll Simulation
Array
Dynamic Programming
Hard
1224. Maximum Equal Frequency
Array
Hash Table
Hard
1226. The Dining Philosophers
Concurrency
Medium
1227. Airplane Seat Assignment Probability
Brainteaser
Math
Dynamic Programming
Probability and Statistics
Medium
1228. Missing Number In Arithmetic Progression
Array
Math
Easy
1229. Meeting Scheduler
Array
Two Pointers
Sorting
Medium
1230. Toss Strange Coins
Array
Math
Dynamic Programming
Probability and Statistics
Medium
1231. Divide Chocolate
Array
Binary Search
Hard
1232. Check If It Is a Straight Line
Geometry
Array
Math
Easy
1233. Remove Sub-Folders from the Filesystem
Depth-First Search
Trie
Array
String
Medium
1234. Replace the Substring for Balanced String
String
Sliding Window
Medium
1235. Maximum Profit in Job Scheduling
Array
Binary Search
Dynamic Programming
Sorting
Hard
1236. Web Crawler
Depth-First Search
Breadth-First Search
String
Interactive
Medium
1237. Find Positive Integer Solution for a Given Equation
Math
Two Pointers
Binary Search
Interactive
Medium
1238. Circular Permutation in Binary Representation
Bit Manipulation
Math
Backtracking
Medium
1239. Maximum Length of a Concatenated String with Unique Characters
Bit Manipulation
Array
String
Backtracking
Medium
1240. Tiling a Rectangle with the Fewest Squares
Backtracking
Hard
1242. Web Crawler Multithreaded
Depth-First Search
Breadth-First Search
Concurrency
Medium
1243. Array Transformation
Array
Simulation
Easy
1244. Design A Leaderboard
Design
Hash Table
Sorting
Medium
1245. Tree Diameter
Tree
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Medium
1246. Palindrome Removal
Array
Dynamic Programming
Hard
1247. Minimum Swaps to Make Strings Equal
Greedy
Math
String
Medium
1248. Count Number of Nice Subarrays
Array
Hash Table
Math
Prefix Sum
Sliding Window
Medium
1249. Minimum Remove to Make Valid Parentheses
Stack
String
Medium
1250. Check If It Is a Good Array
Array
Math
Number Theory
Hard
1252. Cells with Odd Values in a Matrix
Array
Math
Simulation
Easy
1253. Reconstruct a 2-Row Binary Matrix
Greedy
Array
Matrix
Medium
1254. Number of Closed Islands
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
1255. Maximum Score Words Formed by Letters
Bit Manipulation
Array
String
Dynamic Programming
Backtracking
Bitmask
Hard
1256. Encode Number
Bit Manipulation
Math
String
Medium
1257. Smallest Common Region
Tree
Depth-First Search
Breadth-First Search
Array
Hash Table
String
Medium
1258. Synonymous Sentences
Sort
Union Find
Array
Hash Table
String
Backtracking
Medium
1259. Handshakes That Don't Cross
Math
Dynamic Programming
Hard
1260. Shift 2D Grid
Array
Matrix
Simulation
Easy
1261. Find Elements in a Contaminated Binary Tree
Tree
Depth-First Search
Breadth-First Search
Design
Hash Table
Binary Tree
Medium
1262. Greatest Sum Divisible by Three
Greedy
Array
Dynamic Programming
Sorting
Medium
1263. Minimum Moves to Move a Box to Their Target Location
Breadth-First Search
Array
Matrix
Heap (Priority Queue)
Hard
1265. Print Immutable Linked List in Reverse
Stack
Recursion
Linked List
Two Pointers
Medium
1266. Minimum Time Visiting All Points
Geometry
Array
Math
Easy
1267. Count Servers that Communicate
Depth-First Search
Breadth-First Search
Union Find
Array
Counting
Matrix
Medium
1268. Search Suggestions System
Trie
Array
String
Binary Search
Sorting
Heap (Priority Queue)
Medium
1269. Number of Ways to Stay in the Same Place After Some Steps
Dynamic Programming
Hard
1271. Hexspeak
Math
String
Easy
1272. Remove Interval
Array
Medium
1273. Delete Tree Nodes
Tree
Depth-First Search
Breadth-First Search
Array
Medium
1274. Number of Ships in a Rectangle
Array
Divide and Conquer
Interactive
Hard
1275. Find Winner on a Tic Tac Toe Game
Array
Hash Table
Matrix
Simulation
Easy
1276. Number of Burgers with No Waste of Ingredients
Math
Medium
1277. Count Square Submatrices with All Ones
Array
Dynamic Programming
Matrix
Medium
1278. Palindrome Partitioning III
String
Dynamic Programming
Hard
1279. Traffic Light Controlled Intersection
Concurrency
Easy
1281. Subtract the Product and Sum of Digits of an Integer
Math
Easy
1282. Group the People Given the Group Size They Belong To
Greedy
Array
Hash Table
Medium
1283. Find the Smallest Divisor Given a Threshold
Array
Binary Search
Medium
1284. Minimum Number of Flips to Convert Binary Matrix to Zero Matrix
Bit Manipulation
Breadth-First Search
Array
Hash Table
Matrix
Hard
1286. Iterator for Combination
Design
String
Backtracking
Iterator
Medium
1287. Element Appearing More Than 25% In Sorted Array
Array
Easy
1288. Remove Covered Intervals
Array
Sorting
Medium
1289. Minimum Falling Path Sum II
Array
Dynamic Programming
Matrix
Hard
1290. Convert Binary Number in a Linked List to Integer
Linked List
Math
Easy
1291. Sequential Digits
Enumeration
Medium
1292. Maximum Side Length of a Square with Sum Less than or Equal to Threshold
Array
Binary Search
Matrix
Prefix Sum
Medium
1293. Shortest Path in a Grid with Obstacles Elimination
Breadth-First Search
Array
Matrix
Hard
1295. Find Numbers with Even Number of Digits
Array
Math
Easy
1296. Divide Array in Sets of K Consecutive Numbers
Greedy
Array
Hash Table
Sorting
Medium
1297. Maximum Number of Occurrences of a Substring
Hash Table
String
Sliding Window
Medium
1298. Maximum Candies You Can Get from Boxes
Breadth-First Search
Graph
Array
Hard
1299. Replace Elements with Greatest Element on Right Side
Array
Easy
1300. Sum of Mutated Array Closest to Target
Array
Binary Search
Sorting
Medium
1301. Number of Paths with Max Score
Array
Dynamic Programming
Matrix
Hard
1302. Deepest Leaves Sum
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
1304. Find N Unique Integers Sum up to Zero
Array
Math
Easy
1305. All Elements in Two Binary Search Trees
Tree
Depth-First Search
Binary Search Tree
Binary Tree
Sorting
Medium
1306. Jump Game III
Depth-First Search
Breadth-First Search
Array
Medium
1307. Verbal Arithmetic Puzzle
Array
Math
String
Backtracking
Hard
1309. Decrypt String from Alphabet to Integer Mapping
String
Easy
1310. XOR Queries of a Subarray
Bit Manipulation
Array
Prefix Sum
Medium
1311. Get Watched Videos by Your Friends
Breadth-First Search
Graph
Array
Hash Table
Sorting
Medium
1312. Minimum Insertion Steps to Make a String Palindrome
String
Dynamic Programming
Hard
1313. Decompress Run-Length Encoded List
Array
Easy
1314. Matrix Block Sum
Array
Matrix
Prefix Sum
Medium
1315. Sum of Nodes with Even-Valued Grandparent
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
1316. Distinct Echo Substrings
Trie
String
Hash Function
Rolling Hash
Hard
1317. Convert Integer to the Sum of Two No-Zero Integers
Math
Easy
1318. Minimum Flips to Make a OR b Equal to c
Bit Manipulation
Medium
1319. Number of Operations to Make Network Connected
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
1320. Minimum Distance to Type a Word Using Two Fingers
String
Dynamic Programming
Hard
1323. Maximum 69 Number
Greedy
Math
Easy
1324. Print Words Vertically
Array
String
Simulation
Medium
1325. Delete Leaves With a Given Value
Tree
Depth-First Search
Binary Tree
Medium
1326. Minimum Number of Taps to Open to Water a Garden
Greedy
Array
Dynamic Programming
Hard
1328. Break a Palindrome
Greedy
String
Medium
1329. Sort the Matrix Diagonally
Array
Matrix
Sorting
Medium
1330. Reverse Subarray To Maximize Array Value
Greedy
Array
Math
Hard
1331. Rank Transform of an Array
Array
Hash Table
Sorting
Easy
1332. Remove Palindromic Subsequences
Two Pointers
String
Easy
1333. Filter Restaurants by Vegan-Friendly, Price and Distance
Array
Sorting
Medium
1334. Find the City With the Smallest Number of Neighbors at a Threshold Distance
Graph
Dynamic Programming
Shortest Path
Medium
1335. Minimum Difficulty of a Job Schedule
Array
Dynamic Programming
Hard
1337. The K Weakest Rows in a Matrix
Array
Binary Search
Matrix
Sorting
Heap (Priority Queue)
Easy
1338. Reduce Array Size to The Half
Greedy
Array
Hash Table
Sorting
Heap (Priority Queue)
Medium
1339. Maximum Product of Splitted Binary Tree
Tree
Depth-First Search
Binary Tree
Medium
1340. Jump Game V
Array
Dynamic Programming
Sorting
Hard
1342. Number of Steps to Reduce a Number to Zero
Bit Manipulation
Math
Easy
1343. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold
Array
Sliding Window
Medium
1344. Angle Between Hands of a Clock
Math
Medium
1345. Jump Game IV
Breadth-First Search
Array
Hash Table
Hard
1346. Check If N and Its Double Exist
Array
Hash Table
Two Pointers
Binary Search
Sorting
Easy
1347. Minimum Number of Steps to Make Two Strings Anagram
Hash Table
String
Counting
Medium
1348. Tweet Counts Per Frequency
Design
Hash Table
Binary Search
Ordered Set
Sorting
Medium
1349. Maximum Students Taking Exam
Bit Manipulation
Array
Dynamic Programming
Bitmask
Matrix
Hard
1351. Count Negative Numbers in a Sorted Matrix
Array
Binary Search
Matrix
Easy
1352. Product of the Last K Numbers
Design
Array
Math
Data Stream
Prefix Sum
Medium
1353. Maximum Number of Events That Can Be Attended
Greedy
Array
Sorting
Heap (Priority Queue)
Medium
1354. Construct Target Array With Multiple Sums
Array
Heap (Priority Queue)
Hard
1356. Sort Integers by The Number of 1 Bits
Bit Manipulation
Array
Counting
Sorting
Easy
1357. Apply Discount Every n Orders
Design
Array
Hash Table
Medium
1358. Number of Substrings Containing All Three Characters
Hash Table
String
Sliding Window
Medium
1359. Count All Valid Pickup and Delivery Options
Math
Dynamic Programming
Combinatorics
Hard
1360. Number of Days Between Two Dates
Math
String
Easy
1361. Validate Binary Tree Nodes
Tree
Depth-First Search
Breadth-First Search
Union Find
Graph
Binary Tree
Medium
1362. Closest Divisors
Math
Medium
1363. Largest Multiple of Three
Greedy
Array
Math
Dynamic Programming
Sorting
Hard
1365. How Many Numbers Are Smaller Than the Current Number
Array
Hash Table
Counting Sort
Sorting
Easy
1366. Rank Teams by Votes
Array
Hash Table
String
Counting
Sorting
Medium
1367. Linked List in Binary Tree
Tree
Depth-First Search
Linked List
Binary Tree
Medium
1368. Minimum Cost to Make at Least One Valid Path in a Grid
Breadth-First Search
Graph
Array
Matrix
Shortest Path
Heap (Priority Queue)
Hard
1370. Increasing Decreasing String
Hash Table
String
Counting
Easy
1371. Find the Longest Substring Containing Vowels in Even Counts
Bit Manipulation
Hash Table
String
Prefix Sum
Medium
1372. Longest ZigZag Path in a Binary Tree
Tree
Depth-First Search
Dynamic Programming
Binary Tree
Medium
1373. Maximum Sum BST in Binary Tree
Tree
Depth-First Search
Binary Search Tree
Dynamic Programming
Binary Tree
Hard
1374. Generate a String With Characters That Have Odd Counts
String
Easy
1375. Number of Times Binary String Is Prefix-Aligned
Array
Medium
1376. Time Needed to Inform All Employees
Tree
Depth-First Search
Breadth-First Search
Medium
1377. Frog Position After T Seconds
Tree
Depth-First Search
Breadth-First Search
Graph
Hard
1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
1380. Lucky Numbers in a Matrix
Array
Matrix
Easy
1381. Design a Stack With Increment Operation
Stack
Design
Array
Medium
1382. Balance a Binary Search Tree
Greedy
Tree
Depth-First Search
Binary Search Tree
Divide and Conquer
Binary Tree
Medium
1383. Maximum Performance of a Team
Greedy
Array
Sorting
Heap (Priority Queue)
Hard
1385. Find the Distance Value Between Two Arrays
Array
Two Pointers
Binary Search
Sorting
Easy
1386. Cinema Seat Allocation
Greedy
Bit Manipulation
Array
Hash Table
Medium
1387. Sort Integers by The Power Value
Memoization
Dynamic Programming
Sorting
Medium
1388. Pizza With 3n Slices
Greedy
Array
Dynamic Programming
Heap (Priority Queue)
Hard
1389. Create Target Array in the Given Order
Array
Simulation
Easy
1390. Four Divisors
Array
Math
Medium
1391. Check if There is a Valid Path in a Grid
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
1392. Longest Happy Prefix
String
String Matching
Hash Function
Rolling Hash
Hard
1394. Find Lucky Integer in an Array
Array
Hash Table
Counting
Easy
1395. Count Number of Teams
Binary Indexed Tree
Segment Tree
Array
Dynamic Programming
Medium
1396. Design Underground System
Design
Hash Table
String
Medium
1397. Find All Good Strings
String
Dynamic Programming
String Matching
Hard
1399. Count Largest Group
Hash Table
Math
Easy
1400. Construct K Palindrome Strings
Greedy
Hash Table
String
Counting
Medium
1401. Circle and Rectangle Overlapping
Geometry
Math
Medium
1402. Reducing Dishes
Greedy
Array
Dynamic Programming
Sorting
Hard
1403. Minimum Subsequence in Non-Increasing Order
Greedy
Array
Sorting
Easy
1404. Number of Steps to Reduce a Number in Binary Representation to One
Bit Manipulation
String
Simulation
Medium
1405. Longest Happy String
Greedy
String
Heap (Priority Queue)
Medium
1406. Stone Game III
Array
Math
Dynamic Programming
Game Theory
Hard
1408. String Matching in an Array
Array
String
String Matching
Easy
1409. Queries on a Permutation With Key
Binary Indexed Tree
Array
Simulation
Medium
1410. HTML Entity Parser
Hash Table
String
Medium
1411. Number of Ways to Paint N × 3 Grid
Dynamic Programming
Hard
1413. Minimum Value to Get Positive Step by Step Sum
Array
Prefix Sum
Easy
1414. Find the Minimum Number of Fibonacci Numbers Whose Sum Is K
Greedy
Math
Medium
1415. The k-th Lexicographical String of All Happy Strings of Length n
String
Backtracking
Medium
1416. Restore The Array
String
Dynamic Programming
Hard
1417. Reformat The String
String
Easy
1418. Display Table of Food Orders in a Restaurant
Array
Hash Table
String
Ordered Set
Sorting
Medium
1419. Minimum Number of Frogs Croaking
String
Counting
Medium
1420. Build Array Where You Can Find The Maximum Exactly K Comparisons
Dynamic Programming
Prefix Sum
Hard
1422. Maximum Score After Splitting a String
String
Prefix Sum
Easy
1423. Maximum Points You Can Obtain from Cards
Array
Prefix Sum
Sliding Window
Medium
1424. Diagonal Traverse II
Array
Sorting
Heap (Priority Queue)
Medium
1425. Constrained Subsequence Sum
Queue
Array
Dynamic Programming
Sliding Window
Monotonic Queue
Heap (Priority Queue)
Hard
1426. Counting Elements
Array
Hash Table
Easy
1427. Perform String Shifts
Array
Math
String
Easy
1428. Leftmost Column with at Least a One
Array
Binary Search
Interactive
Matrix
Medium
1429. First Unique Number
Design
Queue
Array
Hash Table
Data Stream
Medium
1430. Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
1431. Kids With the Greatest Number of Candies
Array
Easy
1432. Max Difference You Can Get From Changing an Integer
Greedy
Math
Medium
1433. Check If a String Can Break Another String
Greedy
String
Sorting
Medium
1434. Number of Ways to Wear Different Hats to Each Other
Bit Manipulation
Array
Dynamic Programming
Bitmask
Hard
1436. Destination City
Array
Hash Table
String
Easy
1437. Check If All 1's Are at Least Length K Places Away
Array
Easy
1438. Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit
Queue
Array
Ordered Set
Sliding Window
Monotonic Queue
Heap (Priority Queue)
Medium
1439. Find the Kth Smallest Sum of a Matrix With Sorted Rows
Array
Binary Search
Matrix
Heap (Priority Queue)
Hard
1441. Build an Array With Stack Operations
Stack
Array
Simulation
Medium
1442. Count Triplets That Can Form Two Arrays of Equal XOR
Bit Manipulation
Array
Hash Table
Math
Prefix Sum
Medium
1443. Minimum Time to Collect All Apples in a Tree
Tree
Depth-First Search
Breadth-First Search
Hash Table
Medium
1444. Number of Ways of Cutting a Pizza
Memoization
Array
Dynamic Programming
Matrix
Prefix Sum
Hard
1446. Consecutive Characters
String
Easy
1447. Simplified Fractions
Math
String
Number Theory
Medium
1448. Count Good Nodes in Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
1449. Form Largest Integer With Digits That Add up to Target
Array
Dynamic Programming
Hard
1450. Number of Students Doing Homework at a Given Time
Array
Easy
1451. Rearrange Words in a Sentence
String
Sorting
Medium
1452. People Whose List of Favorite Companies Is Not a Subset of Another List
Array
Hash Table
String
Medium
1453. Maximum Number of Darts Inside of a Circular Dartboard
Geometry
Array
Math
Hard
1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence
Two Pointers
String
String Matching
Easy
1456. Maximum Number of Vowels in a Substring of Given Length
String
Sliding Window
Medium
1457. Pseudo-Palindromic Paths in a Binary Tree
Bit Manipulation
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
1458. Max Dot Product of Two Subsequences
Array
Dynamic Programming
Hard
1460. Make Two Arrays Equal by Reversing Subarrays
Array
Hash Table
Sorting
Easy
1461. Check If a String Contains All Binary Codes of Size K
Bit Manipulation
Hash Table
String
Hash Function
Rolling Hash
Medium
1462. Course Schedule IV
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Medium
1463. Cherry Pickup II
Array
Dynamic Programming
Matrix
Hard
1464. Maximum Product of Two Elements in an Array
Array
Sorting
Heap (Priority Queue)
Easy
1465. Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts
Greedy
Array
Sorting
Medium
1466. Reorder Routes to Make All Paths Lead to the City Zero
Depth-First Search
Breadth-First Search
Graph
Medium
1467. Probability of a Two Boxes Having The Same Number of Distinct Balls
Array
Math
Dynamic Programming
Backtracking
Combinatorics
Probability and Statistics
Hard
1469. Find All The Lonely Nodes
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Easy
1470. Shuffle the Array
Array
Easy
1471. The k Strongest Values in an Array
Array
Two Pointers
Sorting
Medium
1472. Design Browser History
Stack
Design
Array
Linked List
Data Stream
Doubly-Linked List
Medium
1473. Paint House III
Array
Dynamic Programming
Hard
1474. Delete N Nodes After M Nodes of a Linked List
Linked List
Easy
1475. Final Prices With a Special Discount in a Shop
Stack
Array
Monotonic Stack
Easy
1476. Subrectangle Queries
Design
Array
Matrix
Medium
1477. Find Two Non-overlapping Sub-arrays Each With Target Sum
Array
Hash Table
Binary Search
Dynamic Programming
Sliding Window
Medium
1478. Allocate Mailboxes
Array
Math
Dynamic Programming
Sorting
Hard
1480. Running Sum of 1d Array
Array
Prefix Sum
Easy
1481. Least Number of Unique Integers after K Removals
Greedy
Array
Hash Table
Counting
Sorting
Medium
1482. Minimum Number of Days to Make m Bouquets
Array
Binary Search
Medium
1483. Kth Ancestor of a Tree Node
Tree
Depth-First Search
Breadth-First Search
Design
Binary Search
Dynamic Programming
Hard
1485. Clone Binary Tree With Random Pointer
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Medium
1486. XOR Operation in an Array
Bit Manipulation
Math
Easy
1487. Making File Names Unique
Array
Hash Table
String
Medium
1488. Avoid Flood in The City
Greedy
Array
Hash Table
Binary Search
Heap (Priority Queue)
Medium
1489. Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree
Union Find
Graph
Minimum Spanning Tree
Sorting
Strongly Connected Component
Hard
1490. Clone N-ary Tree
Tree
Depth-First Search
Breadth-First Search
Hash Table
Medium
1491. Average Salary Excluding the Minimum and Maximum Salary
Array
Sorting
Easy
1492. The kth Factor of n
Math
Number Theory
Medium
1493. Longest Subarray of 1's After Deleting One Element
Array
Dynamic Programming
Sliding Window
Medium
1494. Parallel Courses II
Bit Manipulation
Graph
Dynamic Programming
Bitmask
Hard
1496. Path Crossing
Hash Table
String
Easy
1497. Check If Array Pairs Are Divisible by k
Array
Hash Table
Counting
Medium
1498. Number of Subsequences That Satisfy the Given Sum Condition
Array
Two Pointers
Binary Search
Sorting
Medium
1499. Max Value of Equation
Queue
Array
Sliding Window
Monotonic Queue
Heap (Priority Queue)
Hard
1500. Design a File Sharing System
Design
Hash Table
Data Stream
Sorting
Heap (Priority Queue)
Medium
1502. Can Make Arithmetic Progression From Sequence
Array
Sorting
Easy
1503. Last Moment Before All Ants Fall Out of a Plank
Brainteaser
Array
Simulation
Medium
1504. Count Submatrices With All Ones
Stack
Array
Dynamic Programming
Matrix
Monotonic Stack
Medium
1505. Minimum Possible Integer After at Most K Adjacent Swaps On Digits
Greedy
Binary Indexed Tree
Segment Tree
String
Hard
1506. Find Root of N-Ary Tree
Bit Manipulation
Tree
Depth-First Search
Hash Table
Medium
1507. Reformat Date
String
Easy
1508. Range Sum of Sorted Subarray Sums
Array
Two Pointers
Binary Search
Prefix Sum
Sorting
Medium
1509. Minimum Difference Between Largest and Smallest Value in Three Moves
Greedy
Array
Sorting
Medium
1510. Stone Game IV
Math
Dynamic Programming
Game Theory
Hard
1512. Number of Good Pairs
Array
Hash Table
Math
Counting
Easy
1513. Number of Substrings With Only 1s
Math
String
Medium
1514. Path with Maximum Probability
Graph
Array
Shortest Path
Heap (Priority Queue)
Medium
1515. Best Position for a Service Centre
Geometry
Array
Math
Randomized
Hard
1516. Move Sub-Tree of N-Ary Tree
Tree
Depth-First Search
Hard
1518. Water Bottles
Math
Simulation
Easy
1519. Number of Nodes in the Sub-Tree With the Same Label
Tree
Depth-First Search
Breadth-First Search
Hash Table
Counting
Medium
1520. Maximum Number of Non-Overlapping Substrings
Greedy
String
Hard
1521. Find a Value of a Mysterious Function Closest to Target
Bit Manipulation
Segment Tree
Array
Binary Search
Hard
1522. Diameter of N-Ary Tree
Tree
Depth-First Search
Medium
1523. Count Odd Numbers in an Interval Range
Math
Easy
1524. Number of Sub-arrays With Odd Sum
Array
Math
Dynamic Programming
Prefix Sum
Medium
1525. Number of Good Ways to Split a String
Bit Manipulation
Hash Table
String
Dynamic Programming
Medium
1526. Minimum Number of Increments on Subarrays to Form a Target Array
Stack
Greedy
Array
Dynamic Programming
Monotonic Stack
Hard
1528. Shuffle String
Array
String
Easy
1529. Minimum Suffix Flips
Greedy
String
Medium
1530. Number of Good Leaf Nodes Pairs
Tree
Depth-First Search
Binary Tree
Medium
1531. String Compression II
String
Dynamic Programming
Hard
1533. Find the Index of the Large Integer
Array
Binary Search
Interactive
Medium
1534. Count Good Triplets
Array
Enumeration
Easy
1535. Find the Winner of an Array Game
Array
Simulation
Medium
1536. Minimum Swaps to Arrange a Binary Grid
Greedy
Array
Matrix
Medium
1537. Get the Maximum Score
Greedy
Array
Two Pointers
Dynamic Programming
Hard
1538. Guess the Majority in a Hidden Array
Array
Math
Interactive
Medium
1539. Kth Missing Positive Number
Array
Binary Search
Easy
1540. Can Convert String in K Moves
Hash Table
String
Medium
1541. Minimum Insertions to Balance a Parentheses String
Stack
Greedy
String
Medium
1542. Find Longest Awesome Substring
Bit Manipulation
Hash Table
String
Hard
1544. Make The String Great
Stack
String
Easy
1545. Find Kth Bit in Nth Binary String
Recursion
String
Simulation
Medium
1546. Maximum Number of Non-Overlapping Subarrays With Sum Equals Target
Greedy
Array
Hash Table
Prefix Sum
Medium
1547. Minimum Cost to Cut a Stick
Array
Dynamic Programming
Sorting
Hard
1548. The Most Similar Path in a Graph
Graph
Dynamic Programming
Hard
1550. Three Consecutive Odds
Array
Easy
1551. Minimum Operations to Make Array Equal
Math
Medium
1552. Magnetic Force Between Two Balls
Array
Binary Search
Sorting
Medium
1553. Minimum Number of Days to Eat N Oranges
Memoization
Dynamic Programming
Hard
1554. Strings Differ by One Character
Hash Table
String
Hash Function
Rolling Hash
Medium
1556. Thousand Separator
String
Easy
1557. Minimum Number of Vertices to Reach All Nodes
Graph
Medium
1558. Minimum Numbers of Function Calls to Make Target Array
Greedy
Bit Manipulation
Array
Medium
1559. Detect Cycles in 2D Grid
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
1560. Most Visited Sector in a Circular Track
Array
Simulation
Easy
1561. Maximum Number of Coins You Can Get
Greedy
Array
Math
Game Theory
Sorting
Medium
1562. Find Latest Group of Size M
Array
Hash Table
Binary Search
Simulation
Medium
1563. Stone Game V
Array
Math
Dynamic Programming
Game Theory
Hard
1564. Put Boxes Into the Warehouse I
Greedy
Array
Sorting
Medium
1566. Detect Pattern of Length M Repeated K or More Times
Array
Enumeration
Easy
1567. Maximum Length of Subarray With Positive Product
Greedy
Array
Dynamic Programming
Medium
1568. Minimum Number of Days to Disconnect Island
Depth-First Search
Breadth-First Search
Array
Matrix
Strongly Connected Component
Hard
1569. Number of Ways to Reorder Array to Get Same BST
Tree
Union Find
Binary Search Tree
Memoization
Array
Math
Divide and Conquer
Dynamic Programming
Binary Tree
Combinatorics
Hard
1570. Dot Product of Two Sparse Vectors
Design
Array
Hash Table
Two Pointers
Medium
1572. Matrix Diagonal Sum
Array
Matrix
Easy
1573. Number of Ways to Split a String
Math
String
Medium
1574. Shortest Subarray to be Removed to Make Array Sorted
Stack
Array
Two Pointers
Binary Search
Monotonic Stack
Medium
1575. Count All Possible Routes
Memoization
Array
Dynamic Programming
Hard
1576. Replace All 's to Avoid Consecutive Repeating Characters
String
Easy
1577. Number of Ways Where Square of Number Is Equal to Product of Two Numbers
Array
Hash Table
Math
Two Pointers
Medium
1578. Minimum Time to Make Rope Colorful
Greedy
Array
String
Dynamic Programming
Medium
1579. Remove Max Number of Edges to Keep Graph Fully Traversable
Union Find
Graph
Hard
1580. Put Boxes Into the Warehouse II
Greedy
Array
Sorting
Medium
1582. Special Positions in a Binary Matrix
Array
Matrix
Easy
1583. Count Unhappy Friends
Array
Simulation
Medium
1584. Min Cost to Connect All Points
Union Find
Graph
Array
Minimum Spanning Tree
Medium
1585. Check If String Is Transformable With Substring Sort Operations
Greedy
String
Sorting
Hard
1586. Binary Search Tree Iterator II
Stack
Tree
Design
Binary Search Tree
Binary Tree
Iterator
Medium
1588. Sum of All Odd Length Subarrays
Array
Math
Prefix Sum
Easy
1589. Maximum Sum Obtained of Any Permutation
Greedy
Array
Prefix Sum
Sorting
Medium
1590. Make Sum Divisible by P
Array
Hash Table
Prefix Sum
Medium
1591. Strange Printer II
Graph
Topological Sort
Array
Matrix
Hard
1592. Rearrange Spaces Between Words
String
Easy
1593. Split a String Into the Max Number of Unique Substrings
Hash Table
String
Backtracking
Medium
1594. Maximum Non Negative Product in a Matrix
Array
Dynamic Programming
Matrix
Medium
1595. Minimum Cost to Connect Two Groups of Points
Bit Manipulation
Array
Dynamic Programming
Bitmask
Matrix
Hard
1597. Build Binary Expression Tree From Infix Expression
Stack
Tree
String
Binary Tree
Hard
1598. Crawler Log Folder
Stack
Array
String
Easy
1599. Maximum Profit of Operating a Centennial Wheel
Array
Simulation
Medium
1600. Throne Inheritance
Tree
Depth-First Search
Design
Hash Table
Medium
1601. Maximum Number of Achievable Transfer Requests
Bit Manipulation
Array
Backtracking
Enumeration
Hard
1602. Find Nearest Right Node in Binary Tree
Tree
Breadth-First Search
Binary Tree
Medium
1603. Design Parking System
Design
Counting
Simulation
Easy
1604. Alert Using Same Key-Card Three or More Times in a One Hour Period
Array
Hash Table
String
Sorting
Medium
1605. Find Valid Matrix Given Row and Column Sums
Greedy
Array
Matrix
Medium
1606. Find Servers That Handled Most Number of Requests
Greedy
Array
Ordered Set
Heap (Priority Queue)
Hard
1608. Special Array With X Elements Greater Than or Equal X
Array
Binary Search
Sorting
Easy
1609. Even Odd Tree
Tree
Breadth-First Search
Binary Tree
Medium
1610. Maximum Number of Visible Points
Geometry
Array
Math
Sorting
Sliding Window
Hard
1611. Minimum One Bit Operations to Make Integers Zero
Bit Manipulation
Memoization
Dynamic Programming
Hard
1612. Check If Two Expression Trees are Equivalent
Tree
Depth-First Search
Hash Table
Binary Tree
Counting
Medium
1614. Maximum Nesting Depth of the Parentheses
Stack
String
Easy
1615. Maximal Network Rank
Graph
Medium
1616. Split Two Strings to Make Palindrome
Two Pointers
String
Medium
1617. Count Subtrees With Max Distance Between Cities
Bit Manipulation
Tree
Dynamic Programming
Bitmask
Enumeration
Hard
1618. Maximum Font to Fit a Sentence in a Screen
Array
String
Binary Search
Interactive
Medium
1619. Mean of Array After Removing Some Elements
Array
Sorting
Easy
1620. Coordinate With Maximum Network Quality
Array
Enumeration
Medium
1621. Number of Sets of K Non-Overlapping Line Segments
Math
Dynamic Programming
Combinatorics
Medium
1622. Fancy Sequence
Design
Segment Tree
Math
Hard
1624. Largest Substring Between Two Equal Characters
Hash Table
String
Easy
1625. Lexicographically Smallest String After Applying Operations
Depth-First Search
Breadth-First Search
String
Enumeration
Medium
1626. Best Team With No Conflicts
Array
Dynamic Programming
Sorting
Medium
1627. Graph Connectivity With Threshold
Union Find
Array
Math
Number Theory
Hard
1628. Design an Expression Tree With Evaluate Function
Stack
Tree
Design
Array
Math
Binary Tree
Medium
1629. Slowest Key
Array
String
Easy
1630. Arithmetic Subarrays
Array
Hash Table
Sorting
Medium
1631. Path With Minimum Effort
Depth-First Search
Breadth-First Search
Union Find
Array
Binary Search
Matrix
Heap (Priority Queue)
Medium
1632. Rank Transform of a Matrix
Union Find
Graph
Topological Sort
Array
Matrix
Sorting
Hard
1634. Add Two Polynomials Represented as Linked Lists
Linked List
Math
Two Pointers
Medium
1636. Sort Array by Increasing Frequency
Array
Hash Table
Sorting
Easy
1637. Widest Vertical Area Between Two Points Containing No Points
Array
Sorting
Easy
1638. Count Substrings That Differ by One Character
Hash Table
String
Dynamic Programming
Enumeration
Medium
1639. Number of Ways to Form a Target String Given a Dictionary
Array
String
Dynamic Programming
Hard
1640. Check Array Formation Through Concatenation
Array
Hash Table
Easy
1641. Count Sorted Vowel Strings
Math
Dynamic Programming
Combinatorics
Medium
1642. Furthest Building You Can Reach
Greedy
Array
Heap (Priority Queue)
Medium
1643. Kth Smallest Instructions
Array
Math
Dynamic Programming
Combinatorics
Hard
1644. Lowest Common Ancestor of a Binary Tree II
Tree
Depth-First Search
Binary Tree
Medium
1646. Get Maximum in Generated Array
Array
Simulation
Easy
1647. Minimum Deletions to Make Character Frequencies Unique
Greedy
Hash Table
String
Sorting
Medium
1648. Sell Diminishing-Valued Colored Balls
Greedy
Array
Math
Binary Search
Sorting
Heap (Priority Queue)
Medium
1649. Create Sorted Array through Instructions
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Hard
1650. Lowest Common Ancestor of a Binary Tree III
Tree
Hash Table
Two Pointers
Binary Tree
Medium
1652. Defuse the Bomb
Array
Sliding Window
Easy
1653. Minimum Deletions to Make String Balanced
Stack
String
Dynamic Programming
Medium
1654. Minimum Jumps to Reach Home
Breadth-First Search
Array
Dynamic Programming
Medium
1655. Distribute Repeating Integers
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Hard
1656. Design an Ordered Stream
Design
Array
Hash Table
Data Stream
Easy
1657. Determine if Two Strings Are Close
Hash Table
String
Counting
Sorting
Medium
1658. Minimum Operations to Reduce X to Zero
Array
Hash Table
Binary Search
Prefix Sum
Sliding Window
Medium
1659. Maximize Grid Happiness
Bit Manipulation
Memoization
Dynamic Programming
Bitmask
Hard
1660. Correct a Binary Tree
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Medium
1662. Check If Two String Arrays are Equivalent
Array
String
Easy
1663. Smallest String With A Given Numeric Value
Greedy
String
Medium
1664. Ways to Make a Fair Array
Array
Prefix Sum
Medium
1665. Minimum Initial Energy to Finish Tasks
Greedy
Array
Sorting
Hard
1666. Change the Root of a Binary Tree
Tree
Depth-First Search
Binary Tree
Medium
1668. Maximum Repeating Substring
String
Dynamic Programming
String Matching
Easy
1669. Merge In Between Linked Lists
Linked List
Medium
1670. Design Front Middle Back Queue
Design
Queue
Array
Linked List
Data Stream
Medium
1671. Minimum Number of Removals to Make Mountain Array
Greedy
Array
Binary Search
Dynamic Programming
Hard
1672. Richest Customer Wealth
Array
Matrix
Easy
1673. Find the Most Competitive Subsequence
Stack
Greedy
Array
Monotonic Stack
Medium
1674. Minimum Moves to Make Array Complementary
Array
Hash Table
Prefix Sum
Medium
1675. Minimize Deviation in Array
Greedy
Array
Ordered Set
Heap (Priority Queue)
Hard
1676. Lowest Common Ancestor of a Binary Tree IV
Tree
Depth-First Search
Hash Table
Binary Tree
Medium
1678. Goal Parser Interpretation
String
Easy
1679. Max Number of K-Sum Pairs
Array
Hash Table
Two Pointers
Sorting
Medium
1680. Concatenation of Consecutive Binary Numbers
Bit Manipulation
Math
Simulation
Medium
1681. Minimum Incompatibility
Bit Manipulation
Array
Dynamic Programming
Bitmask
Hard
1682. Longest Palindromic Subsequence II
String
Dynamic Programming
Medium
1684. Count the Number of Consistent Strings
Bit Manipulation
Array
Hash Table
String
Counting
Easy
1685. Sum of Absolute Differences in a Sorted Array
Array
Math
Prefix Sum
Medium
1686. Stone Game VI
Greedy
Array
Math
Game Theory
Sorting
Heap (Priority Queue)
Medium
1687. Delivering Boxes from Storage to Ports
Segment Tree
Queue
Array
Dynamic Programming
Prefix Sum
Monotonic Queue
Heap (Priority Queue)
Hard
1688. Count of Matches in Tournament
Math
Simulation
Easy
1689. Partitioning Into Minimum Number Of Deci-Binary Numbers
Greedy
String
Medium
1690. Stone Game VII
Array
Math
Dynamic Programming
Game Theory
Medium
1691. Maximum Height by Stacking Cuboids
Array
Dynamic Programming
Sorting
Hard
1692. Count Ways to Distribute Candies
Dynamic Programming
Hard
1694. Reformat Phone Number
String
Easy
1695. Maximum Erasure Value
Array
Hash Table
Sliding Window
Medium
1696. Jump Game VI
Queue
Array
Dynamic Programming
Monotonic Queue
Heap (Priority Queue)
Medium
1697. Checking Existence of Edge Length Limited Paths
Union Find
Graph
Array
Two Pointers
Sorting
Hard
1698. Number of Distinct Substrings in a String
Trie
String
Suffix Array
Hash Function
Rolling Hash
Medium
1700. Number of Students Unable to Eat Lunch
Stack
Queue
Array
Simulation
Easy
1701. Average Waiting Time
Array
Simulation
Medium
1702. Maximum Binary String After Change
Greedy
String
Medium
1703. Minimum Adjacent Swaps for K Consecutive Ones
Greedy
Array
Prefix Sum
Sliding Window
Hard
1704. Determine if String Halves Are Alike
String
Counting
Easy
1705. Maximum Number of Eaten Apples
Greedy
Array
Heap (Priority Queue)
Medium
1706. Where Will the Ball Fall
Array
Matrix
Simulation
Medium
1707. Maximum XOR With an Element From Array
Bit Manipulation
Trie
Array
Hard
1708. Largest Subarray Length K
Greedy
Array
Easy
1709. Biggest Window Between Visits
Database
Medium
1710. Maximum Units on a Truck
Greedy
Array
Sorting
Easy
1711. Count Good Meals
Array
Hash Table
Medium
1712. Ways to Split Array Into Three Subarrays
Array
Two Pointers
Binary Search
Prefix Sum
Medium
1713. Minimum Operations to Make a Subsequence
Greedy
Array
Hash Table
Binary Search
Hard
1714. Sum Of Special Evenly-Spaced Elements In Array
Array
Dynamic Programming
Hard
1716. Calculate Money in Leetcode Bank
Math
Easy
1717. Maximum Score From Removing Substrings
Stack
Greedy
String
Medium
1718. Construct the Lexicographically Largest Valid Sequence
Array
Backtracking
Medium
1719. Number Of Ways To Reconstruct A Tree
Tree
Graph
Hard
1720. Decode XORed Array
Bit Manipulation
Array
Easy
1721. Swapping Nodes in a Linked List
Linked List
Two Pointers
Medium
1722. Minimize Hamming Distance After Swap Operations
Depth-First Search
Union Find
Array
Medium
1723. Find Minimum Time to Finish All Jobs
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Hard
1724. Checking Existence of Edge Length Limited Paths II
Union Find
Graph
Minimum Spanning Tree
Hard
1725. Number Of Rectangles That Can Form The Largest Square
Array
Easy
1726. Tuple with Same Product
Array
Hash Table
Counting
Medium
1727. Largest Submatrix With Rearrangements
Greedy
Array
Matrix
Sorting
Medium
1728. Cat and Mouse II
Graph
Topological Sort
Memoization
Array
Math
Dynamic Programming
Game Theory
Matrix
Hard
1730. Shortest Path to Get Food
Breadth-First Search
Array
Matrix
Medium
1732. Find the Highest Altitude
Array
Prefix Sum
Easy
1733. Minimum Number of People to Teach
Greedy
Array
Hash Table
Medium
1734. Decode XORed Permutation
Bit Manipulation
Array
Medium
1735. Count Ways to Make Array With Product
Array
Math
Dynamic Programming
Combinatorics
Number Theory
Hard
1736. Latest Time by Replacing Hidden Digits
Greedy
String
Easy
1737. Change Minimum Characters to Satisfy One of Three Conditions
Hash Table
String
Counting
Prefix Sum
Medium
1738. Find Kth Largest XOR Coordinate Value
Bit Manipulation
Array
Divide and Conquer
Matrix
Prefix Sum
Quickselect
Sorting
Heap (Priority Queue)
Medium
1739. Building Boxes
Greedy
Math
Binary Search
Hard
1740. Find Distance in a Binary Tree
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Medium
1742. Maximum Number of Balls in a Box
Hash Table
Math
Counting
Easy
1743. Restore the Array From Adjacent Pairs
Depth-First Search
Array
Hash Table
Medium
1744. Can You Eat Your Favorite Candy on Your Favorite Day
Array
Prefix Sum
Medium
1745. Palindrome Partitioning IV
String
Dynamic Programming
Hard
1746. Maximum Subarray Sum After One Operation
Array
Dynamic Programming
Medium
1748. Sum of Unique Elements
Array
Hash Table
Counting
Easy
1749. Maximum Absolute Sum of Any Subarray
Array
Dynamic Programming
Medium
1750. Minimum Length of String After Deleting Similar Ends
Two Pointers
String
Medium
1751. Maximum Number of Events That Can Be Attended II
Array
Binary Search
Dynamic Programming
Sorting
Hard
1752. Check if Array Is Sorted and Rotated
Array
Easy
1753. Maximum Score From Removing Stones
Greedy
Math
Heap (Priority Queue)
Medium
1754. Largest Merge Of Two Strings
Greedy
Two Pointers
String
Medium
1755. Closest Subsequence Sum
Bit Manipulation
Array
Two Pointers
Dynamic Programming
Bitmask
Sorting
Hard
1756. Design Most Recently Used Queue
Stack
Design
Binary Indexed Tree
Array
Hash Table
Ordered Set
Medium
1758. Minimum Changes To Make Alternating Binary String
String
Easy
1759. Count Number of Homogenous Substrings
Math
String
Medium
1760. Minimum Limit of Balls in a Bag
Array
Binary Search
Medium
1761. Minimum Degree of a Connected Trio in a Graph
Graph
Enumeration
Hard
1762. Buildings With an Ocean View
Stack
Array
Monotonic Stack
Medium
1763. Longest Nice Substring
Bit Manipulation
Hash Table
String
Divide and Conquer
Sliding Window
Easy
1764. Form Array by Concatenating Subarrays of Another Array
Greedy
Array
Two Pointers
String Matching
Medium
1765. Map of Highest Peak
Breadth-First Search
Array
Matrix
Medium
1766. Tree of Coprimes
Tree
Depth-First Search
Array
Math
Number Theory
Hard
1768. Merge Strings Alternately
Two Pointers
String
Easy
1769. Minimum Number of Operations to Move All Balls to Each Box
Array
String
Prefix Sum
Medium
1770. Maximum Score from Performing Multiplication Operations
Array
Dynamic Programming
Hard
1771. Maximize Palindrome Length From Subsequences
String
Dynamic Programming
Hard
1772. Sort Features by Popularity
Array
Hash Table
String
Sorting
Medium
1773. Count Items Matching a Rule
Array
String
Easy
1774. Closest Dessert Cost
Array
Dynamic Programming
Backtracking
Medium
1775. Equal Sum Arrays With Minimum Number of Operations
Greedy
Array
Hash Table
Counting
Medium
1776. Car Fleet II
Stack
Array
Math
Monotonic Stack
Heap (Priority Queue)
Hard
1778. Shortest Path in a Hidden Grid
Depth-First Search
Breadth-First Search
Array
Interactive
Matrix
Medium
1779. Find Nearest Point That Has the Same X or Y Coordinate
Array
Easy
1780. Check if Number is a Sum of Powers of Three
Math
Medium
1781. Sum of Beauty of All Substrings
Hash Table
String
Counting
Medium
1782. Count Pairs Of Nodes
Graph
Array
Hash Table
Two Pointers
Binary Search
Counting
Sorting
Hard
1784. Check if Binary String Has at Most One Segment of Ones
String
Easy
1785. Minimum Elements to Add to Form a Given Sum
Greedy
Array
Medium
1786. Number of Restricted Paths From First to Last Node
Graph
Topological Sort
Dynamic Programming
Shortest Path
Heap (Priority Queue)
Medium
1787. Make the XOR of All Segments Equal to Zero
Bit Manipulation
Array
Dynamic Programming
Hard
1788. Maximize the Beauty of the Garden
Greedy
Array
Hash Table
Prefix Sum
Hard
1790. Check if One String Swap Can Make Strings Equal
Hash Table
String
Counting
Easy
1791. Find Center of Star Graph
Graph
Easy
1792. Maximum Average Pass Ratio
Greedy
Array
Heap (Priority Queue)
Medium
1793. Maximum Score of a Good Subarray
Stack
Array
Two Pointers
Binary Search
Monotonic Stack
Hard
1794. Count Pairs of Equal Substrings With Minimum Difference
Greedy
Hash Table
String
Medium
1796. Second Largest Digit in a String
Hash Table
String
Easy
1797. Design Authentication Manager
Design
Hash Table
Linked List
Doubly-Linked List
Medium
1798. Maximum Number of Consecutive Values You Can Make
Greedy
Array
Sorting
Medium
1799. Maximize Score After N Operations
Bit Manipulation
Array
Math
Dynamic Programming
Backtracking
Bitmask
Number Theory
Hard
1800. Maximum Ascending Subarray Sum
Array
Easy
1801. Number of Orders in the Backlog
Array
Simulation
Heap (Priority Queue)
Medium
1802. Maximum Value at a Given Index in a Bounded Array
Greedy
Math
Binary Search
Medium
1803. Count Pairs With XOR in a Range
Bit Manipulation
Trie
Array
Hard
1804. Implement Trie II (Prefix Tree)
Design
Trie
Hash Table
String
Medium
1805. Number of Different Integers in a String
Hash Table
String
Easy
1806. Minimum Number of Operations to Reinitialize a Permutation
Array
Math
Simulation
Medium
1807. Evaluate the Bracket Pairs of a String
Array
Hash Table
String
Medium
1808. Maximize Number of Nice Divisors
Recursion
Math
Number Theory
Hard
1810. Minimum Path Cost in a Hidden Grid
Depth-First Search
Breadth-First Search
Graph
Array
Interactive
Matrix
Shortest Path
Heap (Priority Queue)
Medium
1811. Find Interview Candidates
Database
Medium
1812. Determine Color of a Chessboard Square
Math
String
Easy
1813. Sentence Similarity III
Array
Two Pointers
String
Medium
1814. Count Nice Pairs in an Array
Array
Hash Table
Math
Counting
Medium
1815. Maximum Number of Groups Getting Fresh Donuts
Bit Manipulation
Memoization
Array
Dynamic Programming
Bitmask
Hard
1816. Truncate Sentence
Array
String
Easy
1817. Finding the Users Active Minutes
Array
Hash Table
Medium
1818. Minimum Absolute Sum Difference
Array
Binary Search
Ordered Set
Sorting
Medium
1819. Number of Different Subsequences GCDs
Array
Math
Counting
Number Theory
Hard
1820. Maximum Number of Accepted Invitations
Depth-First Search
Graph
Array
Matrix
Medium
1821. Find Customers With Positive Revenue this Year
Database
Easy
1822. Sign of the Product of an Array
Array
Math
Easy
1823. Find the Winner of the Circular Game
Recursion
Queue
Array
Math
Simulation
Medium
1824. Minimum Sideway Jumps
Greedy
Array
Dynamic Programming
Medium
1825. Finding MK Average
Design
Queue
Data Stream
Ordered Set
Heap (Priority Queue)
Hard
1826. Faulty Sensor
Array
Two Pointers
Easy
1827. Minimum Operations to Make the Array Increasing
Greedy
Array
Easy
1828. Queries on Number of Points Inside a Circle
Geometry
Array
Math
Medium
1829. Maximum XOR for Each Query
Bit Manipulation
Array
Prefix Sum
Medium
1830. Minimum Number of Operations to Make String Sorted
Math
String
Combinatorics
Hard
1831. Maximum Transaction Each Day
Database
Medium
1832. Check if the Sentence Is Pangram
Hash Table
String
Easy
1833. Maximum Ice Cream Bars
Greedy
Array
Counting Sort
Sorting
Medium
1834. Single-Threaded CPU
Array
Sorting
Heap (Priority Queue)
Medium
1835. Find XOR Sum of All Pairs Bitwise AND
Bit Manipulation
Array
Math
Hard
1836. Remove Duplicates From an Unsorted Linked List
Hash Table
Linked List
Medium
1837. Sum of Digits in Base K
Math
Easy
1838. Frequency of the Most Frequent Element
Greedy
Array
Binary Search
Prefix Sum
Sorting
Sliding Window
Medium
1839. Longest Substring Of All Vowels in Order
String
Sliding Window
Medium
1840. Maximum Building Height
Array
Math
Sorting
Hard
1841. League Statistics
Database
Medium
1842. Next Palindrome Using Same Digits
Two Pointers
String
Hard
1844. Replace All Digits with Characters
String
Easy
1845. Seat Reservation Manager
Design
Heap (Priority Queue)
Medium
1846. Maximum Element After Decreasing and Rearranging
Greedy
Array
Sorting
Medium
1847. Closest Room
Array
Binary Search
Ordered Set
Sorting
Hard
1848. Minimum Distance to the Target Element
Array
Easy
1849. Splitting a String Into Descending Consecutive Values
String
Backtracking
Enumeration
Medium
1850. Minimum Adjacent Swaps to Reach the Kth Smallest Number
Greedy
Two Pointers
String
Medium
1851. Minimum Interval to Include Each Query
Array
Binary Search
Sorting
Line Sweep
Heap (Priority Queue)
Hard
1852. Distinct Numbers in Each Subarray
Array
Hash Table
Sliding Window
Medium
1853. Convert Date Format
Database
Easy
1854. Maximum Population Year
Array
Counting
Prefix Sum
Easy
1855. Maximum Distance Between a Pair of Values
Array
Two Pointers
Binary Search
Medium
1856. Maximum Subarray Min-Product
Stack
Array
Prefix Sum
Monotonic Stack
Medium
1857. Largest Color Value in a Directed Graph
Graph
Topological Sort
Memoization
Hash Table
Dynamic Programming
Counting
Hard
1858. Longest Word With All Prefixes
Depth-First Search
Trie
Array
String
Medium
1859. Sorting the Sentence
String
Sorting
Easy
1860. Incremental Memory Leak
Math
Simulation
Medium
1861. Rotating the Box
Array
Two Pointers
Matrix
Medium
1862. Sum of Floored Pairs
Array
Math
Binary Search
Prefix Sum
Hard
1863. Sum of All Subset XOR Totals
Bit Manipulation
Array
Math
Backtracking
Combinatorics
Enumeration
Easy
1864. Minimum Number of Swaps to Make the Binary String Alternating
Greedy
String
Medium
1865. Finding Pairs With a Certain Sum
Design
Array
Hash Table
Medium
1866. Number of Ways to Rearrange Sticks With K Sticks Visible
Math
Dynamic Programming
Combinatorics
Hard
1868. Product of Two Run-Length Encoded Arrays
Array
Two Pointers
Medium
1869. Longer Contiguous Segments of Ones than Zeros
String
Easy
1870. Minimum Speed to Arrive on Time
Array
Binary Search
Medium
1871. Jump Game VII
String
Dynamic Programming
Prefix Sum
Sliding Window
Medium
1872. Stone Game VIII
Array
Math
Dynamic Programming
Game Theory
Prefix Sum
Hard
1874. Minimize Product Sum of Two Arrays
Greedy
Array
Sorting
Medium
1876. Substrings of Size Three with Distinct Characters
Hash Table
String
Counting
Sliding Window
Easy
1877. Minimize Maximum Pair Sum in Array
Greedy
Array
Two Pointers
Sorting
Medium
1878. Get Biggest Three Rhombus Sums in a Grid
Array
Math
Matrix
Prefix Sum
Sorting
Heap (Priority Queue)
Medium
1879. Minimum XOR Sum of Two Arrays
Bit Manipulation
Array
Dynamic Programming
Bitmask
Hard
1880. Check if Word Equals Summation of Two Words
String
Easy
1881. Maximum Value after Insertion
Greedy
String
Medium
1882. Process Tasks Using Servers
Array
Heap (Priority Queue)
Medium
1883. Minimum Skips to Arrive at Meeting On Time
Array
Dynamic Programming
Hard
1884. Egg Drop With 2 Eggs and N Floors
Math
Dynamic Programming
Medium
1885. Count Pairs in Two Arrays
Array
Two Pointers
Binary Search
Sorting
Medium
1886. Determine Whether Matrix Can Be Obtained By Rotation
Array
Matrix
Easy
1887. Reduction Operations to Make the Array Elements Equal
Array
Sorting
Medium
1888. Minimum Number of Flips to Make the Binary String Alternating
String
Dynamic Programming
Sliding Window
Medium
1889. Minimum Space Wasted From Packaging
Array
Binary Search
Prefix Sum
Sorting
Hard
1891. Cutting Ribbons
Array
Binary Search
Medium
1893. Check if All the Integers in a Range Are Covered
Array
Hash Table
Prefix Sum
Easy
1894. Find the Student that Will Replace the Chalk
Array
Binary Search
Prefix Sum
Simulation
Medium
1895. Largest Magic Square
Array
Matrix
Prefix Sum
Medium
1896. Minimum Cost to Change the Final Value of Expression
Stack
Math
String
Dynamic Programming
Hard
1897. Redistribute Characters to Make All Strings Equal
Hash Table
String
Counting
Easy
1898. Maximum Number of Removable Characters
Array
Two Pointers
String
Binary Search
Medium
1899. Merge Triplets to Form Target Triplet
Greedy
Array
Medium
1900. The Earliest and Latest Rounds Where Players Compete
Memoization
Dynamic Programming
Hard
1901. Find a Peak Element II
Array
Binary Search
Matrix
Medium
1902. Depth of BST Given Insertion Order
Tree
Binary Search Tree
Array
Binary Tree
Ordered Set
Medium
1903. Largest Odd Number in String
Greedy
Math
String
Easy
1904. The Number of Full Rounds You Have Played
Math
String
Medium
1905. Count Sub Islands
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
1906. Minimum Absolute Difference Queries
Array
Hash Table
Medium
1908. Game of Nim
Bit Manipulation
Brainteaser
Array
Math
Dynamic Programming
Game Theory
Medium
1909. Remove One Element to Make the Array Strictly Increasing
Array
Easy
1910. Remove All Occurrences of a Substring
Stack
String
Simulation
Medium
1911. Maximum Alternating Subsequence Sum
Array
Dynamic Programming
Medium
1912. Design Movie Rental System
Design
Array
Hash Table
Ordered Set
Heap (Priority Queue)
Hard
1913. Maximum Product Difference Between Two Pairs
Array
Sorting
Easy
1914. Cyclically Rotating a Grid
Array
Matrix
Simulation
Medium
1915. Number of Wonderful Substrings
Bit Manipulation
Hash Table
String
Prefix Sum
Medium
1916. Count Ways to Build Rooms in an Ant Colony
Tree
Graph
Topological Sort
Math
Dynamic Programming
Combinatorics
Hard
1918. Kth Smallest Subarray Sum
Array
Binary Search
Sliding Window
Medium
1920. Build Array from Permutation
Array
Simulation
Easy
1921. Eliminate Maximum Number of Monsters
Greedy
Array
Sorting
Medium
1922. Count Good Numbers
Recursion
Math
Medium
1923. Longest Common Subpath
Array
Binary Search
Suffix Array
Hash Function
Rolling Hash
Hard
1924. Erect the Fence II
Geometry
Array
Math
Hard
1925. Count Square Sum Triples
Math
Enumeration
Easy
1926. Nearest Exit from Entrance in Maze
Breadth-First Search
Array
Matrix
Medium
1927. Sum Game
Greedy
Math
String
Game Theory
Medium
1928. Minimum Cost to Reach Destination in Time
Graph
Array
Dynamic Programming
Hard
1929. Concatenation of Array
Array
Simulation
Easy
1930. Unique Length-3 Palindromic Subsequences
Bit Manipulation
Hash Table
String
Prefix Sum
Medium
1931. Painting a Grid With Three Different Colors
Dynamic Programming
Hard
1932. Merge BSTs to Create Single BST
Tree
Depth-First Search
Hash Table
Binary Search
Binary Tree
Hard
1933. Check if String Is Decomposable Into Value-Equal Substrings
String
Easy
1935. Maximum Number of Words You Can Type
Hash Table
String
Easy
1936. Add Minimum Number of Rungs
Greedy
Array
Medium
1937. Maximum Number of Points with Cost
Array
Dynamic Programming
Matrix
Medium
1938. Maximum Genetic Difference Query
Bit Manipulation
Depth-First Search
Trie
Array
Hash Table
Hard
1940. Longest Common Subsequence Between Sorted Arrays
Array
Hash Table
Counting
Medium
1941. Check if All Characters Have Equal Number of Occurrences
Hash Table
String
Counting
Easy
1942. The Number of the Smallest Unoccupied Chair
Array
Hash Table
Heap (Priority Queue)
Medium
1943. Describe the Painting
Array
Hash Table
Prefix Sum
Sorting
Medium
1944. Number of Visible People in a Queue
Stack
Array
Monotonic Stack
Hard
1945. Sum of Digits of String After Convert
String
Simulation
Easy
1946. Largest Number After Mutating Substring
Greedy
Array
String
Medium
1947. Maximum Compatibility Score Sum
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Medium
1948. Delete Duplicate Folders in System
Trie
Array
Hash Table
String
Hash Function
Hard
1950. Maximum of Minimum Values in All Subarrays
Stack
Array
Monotonic Stack
Medium
1952. Three Divisors
Math
Enumeration
Number Theory
Easy
1953. Maximum Number of Weeks for Which You Can Work
Greedy
Array
Medium
1954. Minimum Garden Perimeter to Collect Enough Apples
Math
Binary Search
Medium
1955. Count Number of Special Subsequences
Array
Dynamic Programming
Hard
1956. Minimum Time For K Virus Variants to Spread
Geometry
Array
Math
Binary Search
Enumeration
Hard
1957. Delete Characters to Make Fancy String
String
Easy
1958. Check if Move is Legal
Array
Enumeration
Matrix
Medium
1959. Minimum Total Space Wasted With K Resizing Operations
Array
Dynamic Programming
Medium
1960. Maximum Product of the Length of Two Palindromic Substrings
String
Hash Function
Rolling Hash
Hard
1961. Check If String Is a Prefix of Array
Array
Two Pointers
String
Easy
1962. Remove Stones to Minimize the Total
Greedy
Array
Heap (Priority Queue)
Medium
1963. Minimum Number of Swaps to Make the String Balanced
Stack
Greedy
Two Pointers
String
Medium
1964. Find the Longest Valid Obstacle Course at Each Position
Binary Indexed Tree
Array
Binary Search
Hard
1966. Binary Searchable Numbers in an Unsorted Array
Array
Binary Search
Medium
1967. Number of Strings That Appear as Substrings in Word
Array
String
Easy
1968. Array With Elements Not Equal to Average of Neighbors
Greedy
Array
Sorting
Medium
1969. Minimum Non-Zero Product of the Array Elements
Greedy
Recursion
Math
Medium
1970. Last Day Where You Can Still Cross
Depth-First Search
Breadth-First Search
Union Find
Array
Binary Search
Matrix
Hard
1971. Find if Path Exists in Graph
Depth-First Search
Breadth-First Search
Union Find
Graph
Easy
1973. Count Nodes Equal to Sum of Descendants
Tree
Depth-First Search
Binary Tree
Medium
1974. Minimum Time to Type Word Using Special Typewriter
Greedy
String
Easy
1975. Maximum Matrix Sum
Greedy
Array
Matrix
Medium
1976. Number of Ways to Arrive at Destination
Graph
Topological Sort
Dynamic Programming
Shortest Path
Medium
1977. Number of Ways to Separate Numbers
String
Dynamic Programming
Suffix Array
Hard
1979. Find Greatest Common Divisor of Array
Array
Math
Number Theory
Easy
1980. Find Unique Binary String
Array
Hash Table
String
Backtracking
Medium
1981. Minimize the Difference Between Target and Chosen Elements
Array
Dynamic Programming
Matrix
Medium
1982. Find Array Given Subset Sums
Array
Divide and Conquer
Hard
1983. Widest Pair of Indices With Equal Range Sum
Array
Hash Table
Prefix Sum
Medium
1984. Minimum Difference Between Highest and Lowest of K Scores
Array
Sorting
Sliding Window
Easy
1985. Find the Kth Largest Integer in the Array
Array
String
Divide and Conquer
Quickselect
Sorting
Heap (Priority Queue)
Medium
1986. Minimum Number of Work Sessions to Finish the Tasks
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Medium
1987. Number of Unique Good Subsequences
String
Dynamic Programming
Hard
1989. Maximum Number of People That Can Be Caught in Tag
Greedy
Array
Medium
1991. Find the Middle Index in Array
Array
Prefix Sum
Easy
1992. Find All Groups of Farmland
Depth-First Search
Breadth-First Search
Array
Matrix
Medium
1993. Operations on Tree
Tree
Depth-First Search
Breadth-First Search
Design
Array
Hash Table
Medium
1994. The Number of Good Subsets
Bit Manipulation
Array
Hash Table
Math
Dynamic Programming
Bitmask
Counting
Number Theory
Hard
1995. Count Special Quadruplets
Array
Hash Table
Enumeration
Easy
1996. The Number of Weak Characters in the Game
Stack
Greedy
Array
Sorting
Monotonic Stack
Medium
1997. First Day Where You Have Been in All the Rooms
Array
Dynamic Programming
Medium
1998. GCD Sort of an Array
Union Find
Array
Math
Number Theory
Sorting
Hard
1999. Smallest Greater Multiple Made of Two Digits
Math
Enumeration
Medium
2000. Reverse Prefix of Word
Stack
Two Pointers
String
Easy
2001. Number of Pairs of Interchangeable Rectangles
Array
Hash Table
Math
Counting
Number Theory
Medium
2002. Maximum Product of the Length of Two Palindromic Subsequences
Bit Manipulation
String
Dynamic Programming
Backtracking
Bitmask
Medium
2003. Smallest Missing Genetic Value in Each Subtree
Tree
Depth-First Search
Union Find
Dynamic Programming
Hard
2005. Subtree Removal Game with Fibonacci Tree
Tree
Math
Dynamic Programming
Binary Tree
Game Theory
Hard
2006. Count Number of Pairs With Absolute Difference K
Array
Hash Table
Counting
Easy
2007. Find Original Array From Doubled Array
Greedy
Array
Hash Table
Sorting
Medium
2008. Maximum Earnings From Taxi
Array
Hash Table
Binary Search
Dynamic Programming
Sorting
Medium
2009. Minimum Number of Operations to Make Array Continuous
Array
Hash Table
Binary Search
Sliding Window
Hard
2011. Final Value of Variable After Performing Operations
Array
String
Simulation
Easy
2012. Sum of Beauty in the Array
Array
Medium
2013. Detect Squares
Design
Array
Hash Table
Counting
Medium
2014. Longest Subsequence Repeated k Times
Greedy
String
Backtracking
Counting
Enumeration
Hard
2015. Average Height of Buildings in Each Segment
Greedy
Array
Sorting
Heap (Priority Queue)
Medium
2016. Maximum Difference Between Increasing Elements
Array
Easy
2017. Grid Game
Array
Matrix
Prefix Sum
Medium
2018. Check if Word Can Be Placed In Crossword
Array
Enumeration
Matrix
Medium
2019. The Score of Students Solving Math Expression
Stack
Memoization
Array
Hash Table
Math
String
Dynamic Programming
Hard
2021. Brightest Position on Street
Array
Ordered Set
Prefix Sum
Sorting
Medium
2022. Convert 1D Array Into 2D Array
Array
Matrix
Simulation
Easy
2023. Number of Pairs of Strings With Concatenation Equal to Target
Array
Hash Table
String
Counting
Medium
2024. Maximize the Confusion of an Exam
String
Binary Search
Prefix Sum
Sliding Window
Medium
2025. Maximum Number of Ways to Partition an Array
Array
Hash Table
Counting
Enumeration
Prefix Sum
Hard
2027. Minimum Moves to Convert String
Greedy
String
Easy
2028. Find Missing Observations
Array
Math
Simulation
Medium
2029. Stone Game IX
Greedy
Array
Math
Counting
Game Theory
Medium
2030. Smallest K Length Subsequence With Occurrences of a Letter
Stack
Greedy
String
Monotonic Stack
Hard
2031. Count Subarrays With More Ones Than Zeros
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Medium
2032. Two Out of Three
Bit Manipulation
Array
Hash Table
Easy
2033. Minimum Operations to Make a Uni-Value Grid
Array
Math
Matrix
Sorting
Medium
2034. Stock Price Fluctuation
Design
Hash Table
Data Stream
Ordered Set
Heap (Priority Queue)
Medium
2035. Partition Array Into Two Arrays to Minimize Sum Difference
Bit Manipulation
Array
Two Pointers
Binary Search
Dynamic Programming
Bitmask
Ordered Set
Hard
2036. Maximum Alternating Subarray Sum
Array
Dynamic Programming
Medium
2037. Minimum Number of Moves to Seat Everyone
Greedy
Array
Counting Sort
Sorting
Easy
2038. Remove Colored Pieces if Both Neighbors are the Same Color
Greedy
Math
String
Game Theory
Medium
2039. The Time When the Network Becomes Idle
Breadth-First Search
Graph
Array
Medium
2040. Kth Smallest Product of Two Sorted Arrays
Array
Binary Search
Hard
2042. Check if Numbers Are Ascending in a Sentence
String
Easy
2043. Simple Bank System
Design
Array
Hash Table
Simulation
Medium
2044. Count Number of Maximum Bitwise-OR Subsets
Bit Manipulation
Array
Backtracking
Enumeration
Medium
2045. Second Minimum Time to Reach Destination
Breadth-First Search
Graph
Shortest Path
Hard
2046. Sort Linked List Already Sorted Using Absolute Values
Linked List
Two Pointers
Sorting
Medium
2047. Number of Valid Words in a Sentence
String
Easy
2048. Next Greater Numerically Balanced Number
Hash Table
Math
Backtracking
Counting
Enumeration
Medium
2049. Count Nodes With the Highest Score
Tree
Depth-First Search
Array
Binary Tree
Medium
2050. Parallel Courses III
Graph
Topological Sort
Array
Dynamic Programming
Hard
2052. Minimum Cost to Separate Sentence Into Rows
Array
Dynamic Programming
Medium
2053. Kth Distinct String in an Array
Array
Hash Table
String
Counting
Easy
2054. Two Best Non-Overlapping Events
Array
Binary Search
Dynamic Programming
Sorting
Heap (Priority Queue)
Medium
2055. Plates Between Candles
Array
String
Binary Search
Prefix Sum
Medium
2056. Number of Valid Move Combinations On Chessboard
Array
String
Backtracking
Simulation
Hard
2057. Smallest Index With Equal Value
Array
Easy
2058. Find the Minimum and Maximum Number of Nodes Between Critical Points
Linked List
Medium
2059. Minimum Operations to Convert Number
Breadth-First Search
Array
Medium
2060. Check if an Original String Exists Given Two Encoded Strings
String
Dynamic Programming
Hard
2061. Number of Spaces Cleaning Robot Cleaned
Array
Matrix
Simulation
Medium
2062. Count Vowel Substrings of a String
Hash Table
String
Easy
2063. Vowels of All Substrings
Math
String
Dynamic Programming
Combinatorics
Medium
2064. Minimized Maximum of Products Distributed to Any Store
Greedy
Array
Binary Search
Medium
2065. Maximum Path Quality of a Graph
Graph
Array
Backtracking
Hard
2067. Number of Equal Count Substrings
Hash Table
String
Counting
Sliding Window
Medium
2068. Check Whether Two Strings are Almost Equivalent
Hash Table
String
Counting
Easy
2069. Walking Robot Simulation II
Design
Simulation
Medium
2070. Most Beautiful Item for Each Query
Array
Binary Search
Sorting
Medium
2071. Maximum Number of Tasks You Can Assign
Greedy
Queue
Array
Two Pointers
Binary Search
Sorting
Monotonic Queue
Hard
2073. Time Needed to Buy Tickets
Queue
Array
Simulation
Easy
2074. Reverse Nodes in Even Length Groups
Linked List
Medium
2075. Decode the Slanted Ciphertext
String
Simulation
Medium
2076. Process Restricted Friend Requests
Union Find
Graph
Hard
2077. Paths in Maze That Lead to Same Room
Graph
Medium
2078. Two Furthest Houses With Different Colors
Greedy
Array
Easy
2079. Watering Plants
Array
Simulation
Medium
2080. Range Frequency Queries
Design
Segment Tree
Array
Hash Table
Binary Search
Medium
2081. Sum of k-Mirror Numbers
Math
Enumeration
Hard
2083. Substrings That Begin and End With the Same Letter
Hash Table
Math
String
Counting
Prefix Sum
Medium
2085. Count Common Words With One Occurrence
Array
Hash Table
String
Counting
Easy
2086. Minimum Number of Food Buckets to Feed the Hamsters
Greedy
String
Dynamic Programming
Medium
2087. Minimum Cost Homecoming of a Robot in a Grid
Greedy
Array
Medium
2088. Count Fertile Pyramids in a Land
Array
Dynamic Programming
Matrix
Hard
2089. Find Target Indices After Sorting Array
Array
Binary Search
Sorting
Easy
2090. K Radius Subarray Averages
Array
Sliding Window
Medium
2091. Removing Minimum and Maximum From Array
Greedy
Array
Medium
2092. Find All People With Secret
Depth-First Search
Breadth-First Search
Union Find
Graph
Sorting
Hard
2093. Minimum Cost to Reach City With Discounts
Graph
Shortest Path
Heap (Priority Queue)
Medium
2094. Finding 3-Digit Even Numbers
Array
Hash Table
Enumeration
Sorting
Easy
2095. Delete the Middle Node of a Linked List
Linked List
Two Pointers
Medium
2096. Step-By-Step Directions From a Binary Tree Node to Another
Tree
Depth-First Search
String
Binary Tree
Medium
2097. Valid Arrangement of Pairs
Depth-First Search
Graph
Eulerian Circuit
Hard
2098. Subsequence of Size K With the Largest Even Sum
Greedy
Array
Sorting
Medium
2099. Find Subsequence of Length K With the Largest Sum
Array
Hash Table
Sorting
Heap (Priority Queue)
Easy
2100. Find Good Days to Rob the Bank
Array
Dynamic Programming
Prefix Sum
Medium
2101. Detonate the Maximum Bombs
Depth-First Search
Breadth-First Search
Graph
Geometry
Array
Math
Medium
2102. Sequentially Ordinal Rank Tracker
Design
Data Stream
Ordered Set
Heap (Priority Queue)
Hard
2103. Rings and Rods
Hash Table
String
Easy
2104. Sum of Subarray Ranges
Stack
Array
Monotonic Stack
Medium
2105. Watering Plants II
Array
Two Pointers
Simulation
Medium
2106. Maximum Fruits Harvested After at Most K Steps
Array
Binary Search
Prefix Sum
Sliding Window
Hard
2107. Number of Unique Flavors After Sharing K Candies
Array
Hash Table
Sliding Window
Medium
2108. Find First Palindromic String in the Array
Array
Two Pointers
String
Easy
2109. Adding Spaces to a String
Array
Two Pointers
String
Simulation
Medium
2110. Number of Smooth Descent Periods of a Stock
Array
Math
Dynamic Programming
Medium
2111. Minimum Operations to Make the Array K-Increasing
Array
Binary Search
Hard
2113. Elements in Array After Removing and Replacing Elements
Array
Medium
2114. Maximum Number of Words Found in Sentences
Array
String
Easy
2115. Find All Possible Recipes from Given Supplies
Graph
Topological Sort
Array
Hash Table
String
Medium
2116. Check if a Parentheses String Can Be Valid
Stack
Greedy
String
Medium
2117. Abbreviating the Product of a Range
Math
Hard
2119. A Number After a Double Reversal
Math
Easy
2120. Execution of All Suffix Instructions Staying in a Grid
String
Simulation
Medium
2121. Intervals Between Identical Elements
Array
Hash Table
Prefix Sum
Medium
2122. Recover the Original Array
Array
Hash Table
Two Pointers
Enumeration
Sorting
Hard
2123. Minimum Operations to Remove Adjacent Ones in Matrix
Graph
Array
Matrix
Hard
2124. Check if All A's Appears Before All B's
String
Easy
2125. Number of Laser Beams in a Bank
Array
Math
String
Matrix
Medium
2126. Destroying Asteroids
Greedy
Array
Sorting
Medium
2127. Maximum Employees to Be Invited to a Meeting
Depth-First Search
Graph
Topological Sort
Hard
2128. Remove All Ones With Row and Column Flips
Bit Manipulation
Array
Math
Matrix
Medium
2129. Capitalize the Title
String
Easy
2130. Maximum Twin Sum of a Linked List
Stack
Linked List
Two Pointers
Medium
2131. Longest Palindrome by Concatenating Two Letter Words
Greedy
Array
Hash Table
String
Counting
Medium
2132. Stamping the Grid
Greedy
Array
Matrix
Prefix Sum
Hard
2133. Check if Every Row and Column Contains All Numbers
Array
Hash Table
Matrix
Easy
2134. Minimum Swaps to Group All 1's Together II
Array
Sliding Window
Medium
2135. Count Words Obtained After Adding a Letter
Bit Manipulation
Array
Hash Table
String
Sorting
Medium
2136. Earliest Possible Day of Full Bloom
Greedy
Array
Sorting
Hard
2137. Pour Water Between Buckets to Make Water Levels Equal
Array
Binary Search
Medium
2138. Divide a String Into Groups of Size k
String
Simulation
Easy
2139. Minimum Moves to Reach Target Score
Greedy
Math
Medium
2140. Solving Questions With Brainpower
Array
Dynamic Programming
Medium
2141. Maximum Running Time of N Computers
Greedy
Array
Binary Search
Sorting
Hard
2143. Choose Numbers From Two Arrays in Range
Array
Dynamic Programming
Hard
2144. Minimum Cost of Buying Candies With Discount
Greedy
Array
Sorting
Easy
2145. Count the Hidden Sequences
Array
Prefix Sum
Medium
2146. K Highest Ranked Items Within a Price Range
Breadth-First Search
Array
Matrix
Sorting
Heap (Priority Queue)
Medium
2147. Number of Ways to Divide a Long Corridor
Math
String
Dynamic Programming
Hard
2148. Count Elements With Strictly Smaller and Greater Elements
Array
Counting
Sorting
Easy
2149. Rearrange Array Elements by Sign
Array
Two Pointers
Simulation
Medium
2150. Find All Lonely Numbers in the Array
Array
Hash Table
Counting
Medium
2151. Maximum Good People Based on Statements
Bit Manipulation
Array
Backtracking
Enumeration
Hard
2152. Minimum Number of Lines to Cover Points
Bit Manipulation
Geometry
Array
Hash Table
Math
Dynamic Programming
Backtracking
Bitmask
Medium
2154. Keep Multiplying Found Values by Two
Array
Hash Table
Sorting
Simulation
Easy
2155. All Divisions With the Highest Score of a Binary Array
Array
Medium
2156. Find Substring With Given Hash Value
String
Sliding Window
Hash Function
Rolling Hash
Hard
2157. Groups of Strings
Bit Manipulation
Union Find
String
Hard
2158. Amount of New Area Painted Each Day
Segment Tree
Array
Ordered Set
Hard
2160. Minimum Sum of Four Digit Number After Splitting Digits
Greedy
Math
Sorting
Easy
2161. Partition Array According to Given Pivot
Array
Two Pointers
Simulation
Medium
2162. Minimum Cost to Set Cooking Time
Math
Enumeration
Medium
2163. Minimum Difference in Sums After Removal of Elements
Array
Dynamic Programming
Heap (Priority Queue)
Hard
2164. Sort Even and Odd Indices Independently
Array
Sorting
Easy
2165. Smallest Value of the Rearranged Number
Math
Sorting
Medium
2166. Design Bitset
Design
Array
Hash Table
String
Medium
2167. Minimum Time to Remove All Cars Containing Illegal Goods
String
Dynamic Programming
Hard
2168. Unique Substrings With Equal Digit Frequency
Hash Table
String
Counting
Hash Function
Rolling Hash
Medium
2169. Count Operations to Obtain Zero
Math
Simulation
Easy
2170. Minimum Operations to Make the Array Alternating
Greedy
Array
Hash Table
Counting
Medium
2171. Removing Minimum Number of Magic Beans
Greedy
Array
Enumeration
Prefix Sum
Sorting
Medium
2172. Maximum AND Sum of Array
Bit Manipulation
Array
Dynamic Programming
Bitmask
Hard
2174. Remove All Ones With Row and Column Flips II
Bit Manipulation
Breadth-First Search
Array
Matrix
Medium
2176. Count Equal and Divisible Pairs in an Array
Array
Easy
2177. Find Three Consecutive Integers That Sum to a Given Number
Math
Simulation
Medium
2178. Maximum Split of Positive Even Integers
Greedy
Math
Backtracking
Medium
2179. Count Good Triplets in an Array
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Hard
2180. Count Integers With Even Digit Sum
Math
Simulation
Easy
2181. Merge Nodes in Between Zeros
Linked List
Simulation
Medium
2182. Construct String With Repeat Limit
Greedy
Hash Table
String
Counting
Heap (Priority Queue)
Medium
2183. Count Array Pairs Divisible by K
Array
Math
Number Theory
Hard
2184. Number of Ways to Build Sturdy Brick Wall
Bit Manipulation
Array
Dynamic Programming
Bitmask
Medium
2185. Counting Words With a Given Prefix
Array
String
String Matching
Easy
2186. Minimum Number of Steps to Make Two Strings Anagram II
Hash Table
String
Counting
Medium
2187. Minimum Time to Complete Trips
Array
Binary Search
Medium
2188. Minimum Time to Finish the Race
Array
Dynamic Programming
Hard
2189. Number of Ways to Build House of Cards
Math
Dynamic Programming
Medium
2190. Most Frequent Number Following Key In an Array
Array
Hash Table
Counting
Easy
2191. Sort the Jumbled Numbers
Array
Sorting
Medium
2192. All Ancestors of a Node in a Directed Acyclic Graph
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Medium
2193. Minimum Number of Moves to Make Palindrome
Greedy
Binary Indexed Tree
Two Pointers
String
Hard
2194. Cells in a Range on an Excel Sheet
String
Easy
2195. Append K Integers With Minimal Sum
Greedy
Array
Math
Sorting
Medium
2196. Create Binary Tree From Descriptions
Tree
Array
Hash Table
Binary Tree
Medium
2197. Replace Non-Coprime Numbers in Array
Stack
Array
Math
Number Theory
Hard
2198. Number of Single Divisor Triplets
Math
Medium
2200. Find All K-Distant Indices in an Array
Array
Two Pointers
Easy
2201. Count Artifacts That Can Be Extracted
Array
Hash Table
Simulation
Medium
2202. Maximize the Topmost Element After K Moves
Greedy
Array
Medium
2203. Minimum Weighted Subgraph With the Required Paths
Graph
Shortest Path
Hard
2204. Distance to a Cycle in Undirected Graph
Depth-First Search
Breadth-First Search
Union Find
Graph
Hard
2206. Divide Array Into Equal Pairs
Bit Manipulation
Array
Hash Table
Counting
Easy
2207. Maximize Number of Subsequences in a String
Greedy
String
Prefix Sum
Medium
2208. Minimum Operations to Halve Array Sum
Greedy
Array
Heap (Priority Queue)
Medium
2209. Minimum White Tiles After Covering With Carpets
String
Dynamic Programming
Prefix Sum
Hard
2210. Count Hills and Valleys in an Array
Array
Easy
2211. Count Collisions on a Road
Stack
String
Simulation
Medium
2212. Maximum Points in an Archery Competition
Bit Manipulation
Array
Backtracking
Enumeration
Medium
2213. Longest Substring of One Repeating Character
Segment Tree
Array
String
Ordered Set
Hard
2214. Minimum Health to Beat Game
Greedy
Array
Medium
2215. Find the Difference of Two Arrays
Array
Hash Table
Easy
2216. Minimum Deletions to Make Array Beautiful
Stack
Greedy
Array
Medium
2217. Find Palindrome With Fixed Length
Array
Math
Medium
2218. Maximum Value of K Coins From Piles
Array
Dynamic Programming
Prefix Sum
Hard
2219. Maximum Sum Score of Array
Array
Prefix Sum
Medium
2220. Minimum Bit Flips to Convert Number
Bit Manipulation
Easy
2221. Find Triangular Sum of an Array
Array
Math
Combinatorics
Simulation
Medium
2222. Number of Ways to Select Buildings
String
Dynamic Programming
Prefix Sum
Medium
2223. Sum of Scores of Built Strings
String
Binary Search
String Matching
Suffix Array
Hash Function
Rolling Hash
Hard
2224. Minimum Number of Operations to Convert Time
Greedy
String
Easy
2225. Find Players With Zero or One Losses
Array
Hash Table
Counting
Sorting
Medium
2226. Maximum Candies Allocated to K Children
Array
Binary Search
Medium
2227. Encrypt and Decrypt Strings
Design
Trie
Array
Hash Table
String
Hard
2229. Check if an Array Is Consecutive
Array
Hash Table
Sorting
Easy
2231. Largest Number After Digit Swaps by Parity
Sorting
Heap (Priority Queue)
Easy
2232. Minimize Result by Adding Parentheses to Expression
String
Enumeration
Medium
2233. Maximum Product After K Increments
Greedy
Array
Heap (Priority Queue)
Medium
2234. Maximum Total Beauty of the Gardens
Greedy
Array
Two Pointers
Binary Search
Enumeration
Prefix Sum
Sorting
Hard
2235. Add Two Integers
Math
Easy
2236. Root Equals Sum of Children
Tree
Binary Tree
Easy
2237. Count Positions on Street With Required Brightness
Array
Prefix Sum
Medium
2239. Find Closest Number to Zero
Array
Easy
2240. Number of Ways to Buy Pens and Pencils
Math
Enumeration
Medium
2241. Design an ATM Machine
Greedy
Design
Array
Medium
2242. Maximum Score of a Node Sequence
Graph
Array
Enumeration
Sorting
Hard
2243. Calculate Digit Sum of a String
String
Simulation
Easy
2244. Minimum Rounds to Complete All Tasks
Greedy
Array
Hash Table
Counting
Medium
2245. Maximum Trailing Zeros in a Cornered Path
Array
Matrix
Prefix Sum
Medium
2246. Longest Path With Different Adjacent Characters
Tree
Depth-First Search
Graph
Topological Sort
Array
String
Hard
2247. Maximum Cost of Trip With K Highways
Bit Manipulation
Graph
Dynamic Programming
Bitmask
Hard
2248. Intersection of Multiple Arrays
Array
Hash Table
Counting
Sorting
Easy
2249. Count Lattice Points Inside a Circle
Geometry
Array
Hash Table
Math
Enumeration
Medium
2250. Count Number of Rectangles Containing Each Point
Binary Indexed Tree
Array
Hash Table
Binary Search
Sorting
Medium
2251. Number of Flowers in Full Bloom
Array
Hash Table
Binary Search
Ordered Set
Prefix Sum
Sorting
Hard
2254. Design Video Sharing Platform
Stack
Design
Hash Table
Ordered Set
Hard
2255. Count Prefixes of a Given String
Array
String
Easy
2256. Minimum Average Difference
Array
Prefix Sum
Medium
2257. Count Unguarded Cells in the Grid
Array
Matrix
Simulation
Medium
2258. Escape the Spreading Fire
Breadth-First Search
Array
Binary Search
Matrix
Hard
2259. Remove Digit From Number to Maximize Result
Greedy
String
Enumeration
Easy
2260. Minimum Consecutive Cards to Pick Up
Array
Hash Table
Sliding Window
Medium
2261. K Divisible Elements Subarrays
Trie
Array
Hash Table
Enumeration
Hash Function
Rolling Hash
Medium
2262. Total Appeal of A String
Hash Table
String
Dynamic Programming
Hard
2263. Make Array Non-decreasing or Non-increasing
Greedy
Dynamic Programming
Hard
2264. Largest 3-Same-Digit Number in String
String
Easy
2265. Count Nodes Equal to Average of Subtree
Tree
Depth-First Search
Binary Tree
Medium
2266. Count Number of Texts
Hash Table
Math
String
Dynamic Programming
Medium
2267. Check if There Is a Valid Parentheses String Path
Array
Dynamic Programming
Matrix
Hard
2268. Minimum Number of Keypresses
Greedy
Hash Table
String
Counting
Sorting
Medium
2269. Find the K-Beauty of a Number
Math
String
Sliding Window
Easy
2270. Number of Ways to Split Array
Array
Prefix Sum
Medium
2271. Maximum White Tiles Covered by a Carpet
Greedy
Array
Binary Search
Prefix Sum
Sorting
Sliding Window
Medium
2272. Substring With Largest Variance
Array
Dynamic Programming
Hard
2273. Find Resultant Array After Removing Anagrams
Array
Hash Table
String
Sorting
Easy
2274. Maximum Consecutive Floors Without Special Floors
Array
Sorting
Medium
2275. Largest Combination With Bitwise AND Greater Than Zero
Bit Manipulation
Array
Hash Table
Counting
Medium
2276. Count Integers in Intervals
Design
Segment Tree
Ordered Set
Hard
2277. Closest Node to Path in Tree
Tree
Depth-First Search
Breadth-First Search
Array
Hard
2278. Percentage of Letter in String
String
Easy
2279. Maximum Bags With Full Capacity of Rocks
Greedy
Array
Sorting
Medium
2280. Minimum Lines to Represent a Line Chart
Geometry
Array
Math
Number Theory
Sorting
Medium
2281. Sum of Total Strength of Wizards
Stack
Array
Prefix Sum
Monotonic Stack
Hard
2282. Number of People That Can Be Seen in a Grid
Stack
Array
Matrix
Monotonic Stack
Medium
2283. Check if Number Has Equal Digit Count and Digit Value
Hash Table
String
Counting
Easy
2284. Sender With Largest Word Count
Array
Hash Table
String
Counting
Medium
2285. Maximum Total Importance of Roads
Greedy
Graph
Sorting
Heap (Priority Queue)
Medium
2286. Booking Concert Tickets in Groups
Design
Binary Indexed Tree
Segment Tree
Binary Search
Hard
2287. Rearrange Characters to Make Target String
Hash Table
String
Counting
Easy
2288. Apply Discount to Prices
String
Medium
2289. Steps to Make Array Non-decreasing
Stack
Array
Linked List
Monotonic Stack
Medium
2290. Minimum Obstacle Removal to Reach Corner
Breadth-First Search
Graph
Array
Matrix
Shortest Path
Heap (Priority Queue)
Hard
2291. Maximum Profit From Trading Stocks
Array
Dynamic Programming
Medium
2293. Min Max Game
Array
Simulation
Easy
2294. Partition Array Such That Maximum Difference Is K
Greedy
Array
Sorting
Medium
2295. Replace Elements in an Array
Array
Hash Table
Simulation
Medium
2296. Design a Text Editor
Stack
Design
Linked List
String
Doubly-Linked List
Simulation
Hard
2297. Jump Game VIII
Stack
Graph
Array
Dynamic Programming
Shortest Path
Monotonic Stack
Medium
2299. Strong Password Checker II
String
Easy
2300. Successful Pairs of Spells and Potions
Array
Two Pointers
Binary Search
Sorting
Medium
2301. Match Substring After Replacement
Array
Hash Table
String
String Matching
Hard
2302. Count Subarrays With Score Less Than K
Array
Binary Search
Prefix Sum
Sliding Window
Hard
2303. Calculate Amount Paid in Taxes
Array
Simulation
Easy
2304. Minimum Path Cost in a Grid
Array
Dynamic Programming
Matrix
Medium
2305. Fair Distribution of Cookies
Bit Manipulation
Array
Dynamic Programming
Backtracking
Bitmask
Medium
2306. Naming a Company
Bit Manipulation
Array
Hash Table
String
Enumeration
Hard
2307. Check for Contradictions in Equations
Depth-First Search
Union Find
Graph
Array
Hard
2309. Greatest English Letter in Upper and Lower Case
Hash Table
String
Enumeration
Easy
2310. Sum of Numbers With Units Digit K
Greedy
Math
Dynamic Programming
Enumeration
Medium
2311. Longest Binary Subsequence Less Than or Equal to K
Greedy
Memoization
String
Dynamic Programming
Medium
2312. Selling Pieces of Wood
Memoization
Array
Dynamic Programming
Hard
2313. Minimum Flips in Binary Tree to Get Result
Tree
Depth-First Search
Dynamic Programming
Binary Tree
Hard
2315. Count Asterisks
String
Easy
2316. Count Unreachable Pairs of Nodes in an Undirected Graph
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
2317. Maximum XOR After Operations
Bit Manipulation
Array
Math
Medium
2318. Number of Distinct Roll Sequences
Memoization
Dynamic Programming
Hard
2319. Check if Matrix Is X-Matrix
Array
Matrix
Easy
2320. Count Number of Ways to Place Houses
Dynamic Programming
Medium
2321. Maximum Score Of Spliced Array
Array
Dynamic Programming
Hard
2322. Minimum Score After Removals on a Tree
Bit Manipulation
Tree
Depth-First Search
Array
Hard
2323. Find Minimum Time to Finish All Jobs II
Greedy
Array
Sorting
Medium
2325. Decode the Message
Hash Table
String
Easy
2326. Spiral Matrix IV
Array
Linked List
Matrix
Simulation
Medium
2327. Number of People Aware of a Secret
Queue
Dynamic Programming
Simulation
Medium
2328. Number of Increasing Paths in a Grid
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Memoization
Array
Dynamic Programming
Matrix
Hard
2330. Valid Palindrome IV
Two Pointers
String
Medium
2331. Evaluate Boolean Binary Tree
Tree
Depth-First Search
Binary Tree
Easy
2332. The Latest Time to Catch a Bus
Array
Two Pointers
Binary Search
Sorting
Medium
2333. Minimum Sum of Squared Difference
Greedy
Array
Binary Search
Sorting
Heap (Priority Queue)
Medium
2334. Subarray With Elements Greater Than Varying Threshold
Stack
Union Find
Array
Monotonic Stack
Hard
2335. Minimum Amount of Time to Fill Cups
Greedy
Array
Sorting
Heap (Priority Queue)
Easy
2336. Smallest Number in Infinite Set
Design
Hash Table
Ordered Set
Heap (Priority Queue)
Medium
2337. Move Pieces to Obtain a String
Two Pointers
String
Medium
2338. Count the Number of Ideal Arrays
Math
Dynamic Programming
Combinatorics
Number Theory
Hard
2340. Minimum Adjacent Swaps to Make a Valid Array
Greedy
Array
Medium
2341. Maximum Number of Pairs in Array
Array
Hash Table
Counting
Easy
2342. Max Sum of a Pair With Equal Sum of Digits
Array
Hash Table
Sorting
Heap (Priority Queue)
Medium
2343. Query Kth Smallest Trimmed Number
Array
String
Divide and Conquer
Quickselect
Radix Sort
Sorting
Heap (Priority Queue)
Medium
2344. Minimum Deletions to Make Array Divisible
Array
Math
Number Theory
Sorting
Heap (Priority Queue)
Hard
2345. Finding the Number of Visible Mountains
Stack
Array
Sorting
Monotonic Stack
Medium
2347. Best Poker Hand
Array
Hash Table
Counting
Easy
2348. Number of Zero-Filled Subarrays
Array
Math
Medium
2349. Design a Number Container System
Design
Hash Table
Ordered Set
Heap (Priority Queue)
Medium
2350. Shortest Impossible Sequence of Rolls
Greedy
Array
Hash Table
Hard
2351. First Letter to Appear Twice
Bit Manipulation
Hash Table
String
Counting
Easy
2352. Equal Row and Column Pairs
Array
Hash Table
Matrix
Simulation
Medium
2353. Design a Food Rating System
Design
Array
Hash Table
String
Ordered Set
Heap (Priority Queue)
Medium
2354. Number of Excellent Pairs
Bit Manipulation
Array
Hash Table
Binary Search
Hard
2355. Maximum Number of Books You Can Take
Stack
Array
Dynamic Programming
Monotonic Stack
Hard
2357. Make Array Zero by Subtracting Equal Amounts
Greedy
Array
Hash Table
Sorting
Simulation
Heap (Priority Queue)
Easy
2358. Maximum Number of Groups Entering a Competition
Greedy
Array
Math
Binary Search
Medium
2359. Find Closest Node to Given Two Nodes
Depth-First Search
Graph
Medium
2360. Longest Cycle in a Graph
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Hard
2361. Minimum Costs Using the Train Line
Array
Dynamic Programming
Hard
2363. Merge Similar Items
Array
Hash Table
Ordered Set
Sorting
Easy
2364. Count Number of Bad Pairs
Array
Hash Table
Math
Counting
Medium
2365. Task Scheduler II
Array
Hash Table
Simulation
Medium
2366. Minimum Replacements to Sort the Array
Greedy
Array
Math
Hard
2367. Number of Arithmetic Triplets
Array
Hash Table
Two Pointers
Enumeration
Easy
2368. Reachable Nodes With Restrictions
Tree
Depth-First Search
Breadth-First Search
Union Find
Graph
Array
Hash Table
Medium
2369. Check if There is a Valid Partition For The Array
Array
Dynamic Programming
Medium
2370. Longest Ideal Subsequence
Hash Table
String
Dynamic Programming
Medium
2371. Minimize Maximum Value in a Grid
Union Find
Graph
Topological Sort
Array
Matrix
Sorting
Hard
2373. Largest Local Values in a Matrix
Array
Matrix
Easy
2374. Node With Highest Edge Score
Graph
Hash Table
Medium
2375. Construct Smallest Number From DI String
Stack
Greedy
String
Backtracking
Medium
2376. Count Special Integers
Math
Dynamic Programming
Hard
2378. Choose Edges to Maximize Score in a Tree
Tree
Depth-First Search
Dynamic Programming
Medium
2379. Minimum Recolors to Get K Consecutive Black Blocks
String
Sliding Window
Easy
2380. Time Needed to Rearrange a Binary String
String
Dynamic Programming
Simulation
Medium
2381. Shifting Letters II
Array
String
Prefix Sum
Medium
2382. Maximum Segment Sum After Removals
Union Find
Array
Ordered Set
Prefix Sum
Hard
2383. Minimum Hours of Training to Win a Competition
Greedy
Array
Easy
2384. Largest Palindromic Number
Greedy
Hash Table
String
Counting
Medium
2385. Amount of Time for Binary Tree to Be Infected
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Medium
2386. Find the K-Sum of an Array
Array
Sorting
Heap (Priority Queue)
Hard
2387. Median of a Row Wise Sorted Matrix
Array
Binary Search
Matrix
Medium
2389. Longest Subsequence With Limited Sum
Greedy
Array
Binary Search
Prefix Sum
Sorting
Easy
2390. Removing Stars From a String
Stack
String
Simulation
Medium
2391. Minimum Amount of Time to Collect Garbage
Array
String
Prefix Sum
Medium
2392. Build a Matrix With Conditions
Graph
Topological Sort
Array
Matrix
Hard
2393. Count Strictly Increasing Subarrays
Array
Math
Dynamic Programming
Medium
2395. Find Subarrays With Equal Sum
Array
Hash Table
Easy
2396. Strictly Palindromic Number
Brainteaser
Math
Two Pointers
Medium
2397. Maximum Rows Covered by Columns
Bit Manipulation
Array
Backtracking
Enumeration
Matrix
Medium
2398. Maximum Number of Robots Within Budget
Queue
Array
Binary Search
Prefix Sum
Sliding Window
Monotonic Queue
Heap (Priority Queue)
Hard
2399. Check Distances Between Same Letters
Array
Hash Table
String
Easy
2400. Number of Ways to Reach a Position After Exactly k Steps
Math
Dynamic Programming
Combinatorics
Medium
2401. Longest Nice Subarray
Bit Manipulation
Array
Sliding Window
Medium
2402. Meeting Rooms III
Array
Hash Table
Sorting
Simulation
Heap (Priority Queue)
Hard
2403. Minimum Time to Kill All Monsters
Bit Manipulation
Array
Dynamic Programming
Bitmask
Hard
2404. Most Frequent Even Element
Array
Hash Table
Counting
Easy
2405. Optimal Partition of String
Greedy
Hash Table
String
Medium
2406. Divide Intervals Into Minimum Number of Groups
Greedy
Array
Two Pointers
Prefix Sum
Sorting
Heap (Priority Queue)
Medium
2407. Longest Increasing Subsequence II
Binary Indexed Tree
Segment Tree
Queue
Array
Divide and Conquer
Dynamic Programming
Monotonic Queue
Hard
2408. Design SQL
Design
Array
Hash Table
String
Medium
2409. Count Days Spent Together
Math
String
Easy
2410. Maximum Matching of Players With Trainers
Greedy
Array
Two Pointers
Sorting
Medium
2411. Smallest Subarrays With Maximum Bitwise OR
Bit Manipulation
Array
Binary Search
Sliding Window
Medium
2412. Minimum Money Required Before Transactions
Greedy
Array
Sorting
Hard
2413. Smallest Even Multiple
Math
Number Theory
Easy
2414. Length of the Longest Alphabetical Continuous Substring
String
Medium
2415. Reverse Odd Levels of Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
2416. Sum of Prefix Scores of Strings
Trie
Array
String
Counting
Hard
2417. Closest Fair Integer
Math
Enumeration
Medium
2418. Sort the People
Array
Hash Table
String
Sorting
Easy
2419. Longest Subarray With Maximum Bitwise AND
Bit Manipulation
Brainteaser
Array
Medium
2420. Find All Good Indices
Array
Dynamic Programming
Prefix Sum
Medium
2421. Number of Good Paths
Tree
Union Find
Graph
Array
Hash Table
Sorting
Hard
2422. Merge Operations to Turn Array Into a Palindrome
Greedy
Array
Two Pointers
Medium
2423. Remove Letter To Equalize Frequency
Hash Table
String
Counting
Easy
2424. Longest Uploaded Prefix
Union Find
Design
Binary Indexed Tree
Segment Tree
Hash Table
Binary Search
Ordered Set
Heap (Priority Queue)
Medium
2425. Bitwise XOR of All Pairings
Bit Manipulation
Brainteaser
Array
Medium
2426. Number of Pairs Satisfying Inequality
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Hard
2427. Number of Common Factors
Math
Enumeration
Number Theory
Easy
2428. Maximum Sum of an Hourglass
Array
Matrix
Prefix Sum
Medium
2429. Minimize XOR
Greedy
Bit Manipulation
Medium
2430. Maximum Deletions on a String
String
Dynamic Programming
String Matching
Hash Function
Rolling Hash
Hard
2431. Maximize Total Tastiness of Purchased Fruits
Array
Dynamic Programming
Medium
2432. The Employee That Worked on the Longest Task
Array
Easy
2433. Find The Original Array of Prefix Xor
Bit Manipulation
Array
Medium
2434. Using a Robot to Print the Lexicographically Smallest String
Stack
Greedy
Hash Table
String
Medium
2435. Paths in Matrix Whose Sum Is Divisible by K
Array
Dynamic Programming
Matrix
Hard
2436. Minimum Split Into Subarrays With GCD Greater Than One
Greedy
Array
Math
Dynamic Programming
Number Theory
Medium
2437. Number of Valid Clock Times
String
Enumeration
Easy
2438. Range Product Queries of Powers
Bit Manipulation
Array
Prefix Sum
Medium
2439. Minimize Maximum of Array
Greedy
Array
Binary Search
Dynamic Programming
Prefix Sum
Medium
2440. Create Components With Same Value
Tree
Depth-First Search
Array
Math
Enumeration
Hard
2441. Largest Positive Integer That Exists With Its Negative
Array
Hash Table
Two Pointers
Sorting
Easy
2442. Count Number of Distinct Integers After Reverse Operations
Array
Hash Table
Math
Counting
Medium
2443. Sum of Number and Its Reverse
Math
Enumeration
Medium
2444. Count Subarrays With Fixed Bounds
Queue
Array
Sliding Window
Monotonic Queue
Hard
2445. Number of Nodes With Value One
Tree
Depth-First Search
Breadth-First Search
Array
Binary Tree
Medium
2446. Determine if Two Events Have Conflict
Array
String
Easy
2447. Number of Subarrays With GCD Equal to K
Array
Math
Number Theory
Medium
2448. Minimum Cost to Make Array Equal
Greedy
Array
Binary Search
Prefix Sum
Sorting
Hard
2449. Minimum Number of Operations to Make Arrays Similar
Greedy
Array
Sorting
Hard
2450. Number of Distinct Binary Strings After Applying Operations
Math
String
Medium
2451. Odd String Difference
Array
Hash Table
String
Easy
2452. Words Within Two Edits of Dictionary
Trie
Array
String
Medium
2453. Destroy Sequential Targets
Array
Hash Table
Counting
Medium
2454. Next Greater Element IV
Stack
Array
Binary Search
Sorting
Monotonic Stack
Heap (Priority Queue)
Hard
2455. Average Value of Even Numbers That Are Divisible by Three
Array
Math
Easy
2456. Most Popular Video Creator
Array
Hash Table
String
Sorting
Heap (Priority Queue)
Medium
2457. Minimum Addition to Make Integer Beautiful
Greedy
Math
Medium
2458. Height of Binary Tree After Subtree Removal Queries
Tree
Depth-First Search
Breadth-First Search
Array
Binary Tree
Hard
2459. Sort Array by Moving Items to Empty Space
Greedy
Array
Sorting
Hard
2460. Apply Operations to an Array
Array
Two Pointers
Simulation
Easy
2461. Maximum Sum of Distinct Subarrays With Length K
Array
Hash Table
Sliding Window
Medium
2462. Total Cost to Hire K Workers
Array
Two Pointers
Simulation
Heap (Priority Queue)
Medium
2463. Minimum Total Distance Traveled
Array
Dynamic Programming
Sorting
Hard
2464. Minimum Subarrays in a Valid Split
Array
Math
Dynamic Programming
Number Theory
Medium
2465. Number of Distinct Averages
Array
Hash Table
Two Pointers
Sorting
Easy
2466. Count Ways To Build Good Strings
Dynamic Programming
Medium
2467. Most Profitable Path in a Tree
Tree
Depth-First Search
Breadth-First Search
Graph
Array
Medium
2468. Split Message Based on Limit
String
Binary Search
Enumeration
Hard
2469. Convert the Temperature
Math
Easy
2470. Number of Subarrays With LCM Equal to K
Array
Math
Number Theory
Medium
2471. Minimum Number of Operations to Sort a Binary Tree by Level
Tree
Breadth-First Search
Binary Tree
Medium
2472. Maximum Number of Non-overlapping Palindrome Substrings
Greedy
Two Pointers
String
Dynamic Programming
Hard
2473. Minimum Cost to Buy Apples
Graph
Array
Shortest Path
Heap (Priority Queue)
Medium
2475. Number of Unequal Triplets in Array
Array
Hash Table
Sorting
Easy
2476. Closest Nodes Queries in a Binary Search Tree
Tree
Depth-First Search
Binary Search Tree
Array
Binary Search
Binary Tree
Medium
2477. Minimum Fuel Cost to Report to the Capital
Tree
Depth-First Search
Breadth-First Search
Graph
Medium
2478. Number of Beautiful Partitions
String
Dynamic Programming
Hard
2479. Maximum XOR of Two Non-Overlapping Subtrees
Tree
Depth-First Search
Graph
Trie
Hard
2481. Minimum Cuts to Divide a Circle
Geometry
Math
Easy
2482. Difference Between Ones and Zeros in Row and Column
Array
Matrix
Simulation
Medium
2483. Minimum Penalty for a Shop
String
Prefix Sum
Medium
2484. Count Palindromic Subsequences
String
Dynamic Programming
Hard
2485. Find the Pivot Integer
Math
Prefix Sum
Easy
2486. Append Characters to String to Make Subsequence
Greedy
Two Pointers
String
Medium
2487. Remove Nodes From Linked List
Stack
Recursion
Linked List
Monotonic Stack
Medium
2488. Count Subarrays With Median K
Array
Hash Table
Prefix Sum
Hard
2489. Number of Substrings With Fixed Ratio
Hash Table
Math
String
Prefix Sum
Medium
2490. Circular Sentence
String
Easy
2491. Divide Players Into Teams of Equal Skill
Array
Hash Table
Two Pointers
Sorting
Medium
2492. Minimum Score of a Path Between Two Cities
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
2493. Divide Nodes Into the Maximum Number of Groups
Depth-First Search
Breadth-First Search
Union Find
Graph
Hard
2495. Number of Subarrays Having Even Product
Array
Math
Dynamic Programming
Medium
2496. Maximum Value of a String in an Array
Array
String
Easy
2497. Maximum Star Sum of a Graph
Greedy
Graph
Array
Sorting
Heap (Priority Queue)
Medium
2498. Frog Jump II
Greedy
Array
Binary Search
Medium
2499. Minimum Total Cost to Make Arrays Unequal
Greedy
Array
Hash Table
Counting
Hard
2500. Delete Greatest Value in Each Row
Array
Matrix
Sorting
Simulation
Heap (Priority Queue)
Easy
2501. Longest Square Streak in an Array
Array
Hash Table
Binary Search
Dynamic Programming
Sorting
Medium
2502. Design Memory Allocator
Design
Array
Hash Table
Simulation
Medium
2503. Maximum Number of Points From Grid Queries
Breadth-First Search
Union Find
Array
Two Pointers
Matrix
Sorting
Heap (Priority Queue)
Hard
2505. Bitwise OR of All Subsequence Sums
Bit Manipulation
Brainteaser
Array
Math
Prefix Sum
Medium
2506. Count Pairs Of Similar Strings
Bit Manipulation
Array
Hash Table
String
Counting
Easy
2507. Smallest Value After Replacing With Sum of Prime Factors
Math
Number Theory
Simulation
Medium
2508. Add Edges to Make Degrees of All Nodes Even
Graph
Hash Table
Hard
2509. Cycle Length Queries in a Tree
Tree
Array
Binary Tree
Hard
2510. Check if There is a Path With Equal Number of 0's And 1's
Array
Dynamic Programming
Matrix
Medium
2511. Maximum Enemy Forts That Can Be Captured
Array
Two Pointers
Easy
2512. Reward Top K Students
Array
Hash Table
String
Sorting
Heap (Priority Queue)
Medium
2513. Minimize the Maximum of Two Arrays
Math
Binary Search
Number Theory
Medium
2514. Count Anagrams
Hash Table
Math
String
Combinatorics
Counting
Hard
2515. Shortest Distance to Target String in a Circular Array
Array
String
Easy
2516. Take K of Each Character From Left and Right
Hash Table
String
Sliding Window
Medium
2517. Maximum Tastiness of Candy Basket
Greedy
Array
Binary Search
Sorting
Medium
2518. Number of Great Partitions
Array
Dynamic Programming
Hard
2519. Count the Number of K-Big Indices
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Hard
2520. Count the Digits That Divide a Number
Math
Easy
2521. Distinct Prime Factors of Product of Array
Array
Hash Table
Math
Number Theory
Medium
2522. Partition String Into Substrings With Values at Most K
Greedy
String
Dynamic Programming
Medium
2523. Closest Prime Numbers in Range
Math
Number Theory
Medium
2524. Maximum Frequency Score of a Subarray
Stack
Array
Hash Table
Math
Sliding Window
Hard
2525. Categorize Box According to Criteria
Math
Easy
2526. Find Consecutive Integers from a Data Stream
Design
Queue
Hash Table
Counting
Data Stream
Medium
2527. Find Xor-Beauty of Array
Bit Manipulation
Array
Math
Medium
2528. Maximize the Minimum Powered City
Greedy
Queue
Array
Binary Search
Prefix Sum
Sliding Window
Hard
2529. Maximum Count of Positive Integer and Negative Integer
Array
Binary Search
Counting
Easy
2530. Maximal Score After Applying K Operations
Greedy
Array
Heap (Priority Queue)
Medium
2531. Make Number of Distinct Characters Equal
Hash Table
String
Counting
Medium
2532. Time to Cross a Bridge
Array
Simulation
Heap (Priority Queue)
Hard
2533. Number of Good Binary Strings
Dynamic Programming
Medium
2534. Time Taken to Cross the Door
Queue
Array
Simulation
Hard
2535. Difference Between Element Sum and Digit Sum of an Array
Array
Math
Easy
2536. Increment Submatrices by One
Array
Matrix
Prefix Sum
Medium
2537. Count the Number of Good Subarrays
Array
Hash Table
Sliding Window
Medium
2538. Difference Between Maximum and Minimum Price Sum
Tree
Depth-First Search
Array
Dynamic Programming
Hard
2539. Count the Number of Good Subsequences
Hash Table
Math
String
Combinatorics
Counting
Medium
2540. Minimum Common Value
Array
Hash Table
Two Pointers
Binary Search
Easy
2541. Minimum Operations to Make Array Equal II
Greedy
Array
Math
Medium
2542. Maximum Subsequence Score
Greedy
Array
Sorting
Heap (Priority Queue)
Medium
2543. Check if Point Is Reachable
Math
Number Theory
Hard
2544. Alternating Digit Sum
Math
Easy
2545. Sort the Students by Their Kth Score
Array
Matrix
Sorting
Medium
2546. Apply Bitwise Operations to Make Strings Equal
Bit Manipulation
String
Medium
2547. Minimum Cost to Split an Array
Array
Hash Table
Dynamic Programming
Counting
Hard
2548. Maximum Price to Fill a Bag
Greedy
Array
Sorting
Medium
2549. Count Distinct Numbers on Board
Array
Hash Table
Math
Simulation
Easy
2550. Count Collisions of Monkeys on a Polygon
Recursion
Math
Medium
2551. Put Marbles in Bags
Greedy
Array
Sorting
Heap (Priority Queue)
Hard
2552. Count Increasing Quadruplets
Binary Indexed Tree
Array
Dynamic Programming
Enumeration
Prefix Sum
Hard
2553. Separate the Digits in an Array
Array
Simulation
Easy
2554. Maximum Number of Integers to Choose From a Range I
Greedy
Array
Hash Table
Binary Search
Sorting
Medium
2555. Maximize Win From Two Segments
Array
Binary Search
Sliding Window
Medium
2556. Disconnect Path in a Binary Matrix by at Most One Flip
Depth-First Search
Breadth-First Search
Array
Dynamic Programming
Matrix
Medium
2557. Maximum Number of Integers to Choose From a Range II
Greedy
Array
Binary Search
Sorting
Medium
2558. Take Gifts From the Richest Pile
Array
Simulation
Heap (Priority Queue)
Easy
2559. Count Vowel Strings in Ranges
Array
String
Prefix Sum
Medium
2560. House Robber IV
Greedy
Array
Binary Search
Dynamic Programming
Medium
2561. Rearranging Fruits
Greedy
Sort
Array
Hash Table
Hard
2562. Find the Array Concatenation Value
Array
Two Pointers
Simulation
Easy
2563. Count the Number of Fair Pairs
Array
Two Pointers
Binary Search
Sorting
Medium
2564. Substring XOR Queries
Bit Manipulation
Array
Hash Table
String
Medium
2565. Subsequence With the Minimum Score
Two Pointers
String
Binary Search
Hard
2566. Maximum Difference by Remapping a Digit
Greedy
Math
Easy
2567. Minimum Score by Changing Two Elements
Greedy
Array
Sorting
Medium
2568. Minimum Impossible OR
Bit Manipulation
Brainteaser
Array
Medium
2569. Handling Sum Queries After Update
Segment Tree
Array
Hard
2570. Merge Two 2D Arrays by Summing Values
Array
Hash Table
Two Pointers
Easy
2571. Minimum Operations to Reduce an Integer to 0
Greedy
Bit Manipulation
Dynamic Programming
Medium
2572. Count the Number of Square-Free Subsets
Bit Manipulation
Array
Math
Dynamic Programming
Bitmask
Medium
2573. Find the String with LCP
Greedy
Union Find
Array
String
Dynamic Programming
Matrix
Hard
2574. Left and Right Sum Differences
Array
Prefix Sum
Easy
2575. Find the Divisibility Array of a String
Array
Math
String
Medium
2576. Find the Maximum Number of Marked Indices
Greedy
Array
Two Pointers
Binary Search
Sorting
Medium
2577. Minimum Time to Visit a Cell In a Grid
Breadth-First Search
Graph
Array
Matrix
Shortest Path
Heap (Priority Queue)
Hard
2578. Split With Minimum Sum
Greedy
Math
Sorting
Easy
2579. Count Total Number of Colored Cells
Math
Medium
2580. Count Ways to Group Overlapping Ranges
Array
Sorting
Medium
2581. Count Number of Possible Root Nodes
Tree
Depth-First Search
Array
Hash Table
Dynamic Programming
Hard
2582. Pass the Pillow
Math
Simulation
Easy
2583. Kth Largest Sum in a Binary Tree
Tree
Breadth-First Search
Binary Tree
Sorting
Medium
2584. Split the Array to Make Coprime Products
Array
Hash Table
Math
Number Theory
Hard
2585. Number of Ways to Earn Points
Array
Dynamic Programming
Hard
2586. Count the Number of Vowel Strings in Range
Array
String
Counting
Easy
2587. Rearrange Array to Maximize Prefix Score
Greedy
Array
Prefix Sum
Sorting
Medium
2588. Count the Number of Beautiful Subarrays
Bit Manipulation
Array
Hash Table
Prefix Sum
Medium
2589. Minimum Time to Complete All Tasks
Stack
Greedy
Array
Binary Search
Sorting
Hard
2590. Design a Todo List
Design
Array
Hash Table
String
Sorting
Medium
2591. Distribute Money to Maximum Children
Greedy
Math
Easy
2592. Maximize Greatness of an Array
Greedy
Array
Two Pointers
Sorting
Medium
2593. Find Score of an Array After Marking All Elements
Array
Hash Table
Sorting
Simulation
Heap (Priority Queue)
Medium
2594. Minimum Time to Repair Cars
Array
Binary Search
Medium
2595. Number of Even and Odd Bits
Bit Manipulation
Easy
2596. Check Knight Tour Configuration
Depth-First Search
Breadth-First Search
Array
Matrix
Simulation
Medium
2597. The Number of Beautiful Subsets
Array
Hash Table
Math
Dynamic Programming
Backtracking
Combinatorics
Sorting
Medium
2598. Smallest Missing Non-negative Integer After Operations
Greedy
Array
Hash Table
Math
Medium
2599. Make the Prefix Sum Non-negative
Greedy
Array
Heap (Priority Queue)
Medium
2600. K Items With the Maximum Sum
Greedy
Math
Easy
2601. Prime Subtraction Operation
Greedy
Array
Math
Binary Search
Number Theory
Medium
2602. Minimum Operations to Make All Array Elements Equal
Array
Binary Search
Prefix Sum
Sorting
Medium
2603. Collect Coins in a Tree
Tree
Graph
Topological Sort
Array
Hard
2604. Minimum Time to Eat All Grains
Array
Two Pointers
Binary Search
Sorting
Hard
2605. Form Smallest Number From Two Digit Arrays
Array
Hash Table
Enumeration
Easy
2606. Find the Substring With Maximum Cost
Array
Hash Table
String
Dynamic Programming
Medium
2607. Make K-Subarray Sums Equal
Greedy
Array
Math
Number Theory
Sorting
Medium
2608. Shortest Cycle in a Graph
Breadth-First Search
Graph
Hard
2609. Find the Longest Balanced Substring of a Binary String
String
Easy
2610. Convert an Array Into a 2D Array With Conditions
Array
Hash Table
Medium
2611. Mice and Cheese
Greedy
Array
Sorting
Heap (Priority Queue)
Medium
2612. Minimum Reverse Operations
Breadth-First Search
Array
Ordered Set
Hard
2613. Beautiful Pairs
Geometry
Array
Math
Divide and Conquer
Ordered Set
Sorting
Hard
2614. Prime In Diagonal
Array
Math
Matrix
Number Theory
Easy
2615. Sum of Distances
Array
Hash Table
Prefix Sum
Medium
2616. Minimize the Maximum Difference of Pairs
Greedy
Array
Binary Search
Dynamic Programming
Sorting
Medium
2617. Minimum Number of Visited Cells in a Grid
Stack
Breadth-First Search
Union Find
Array
Dynamic Programming
Matrix
Monotonic Stack
Heap (Priority Queue)
Hard
2618. Check if Object Instance of Class
JavaScript
Medium
2619. Array Prototype Last
JavaScript
Easy
2620. Counter
JavaScript
Easy
2621. Sleep
JavaScript
Easy
2622. Cache With Time Limit
JavaScript
Medium
2623. Memoize
JavaScript
Medium
2624. Snail Traversal
JavaScript
Medium
2625. Flatten Deeply Nested Array
JavaScript
Medium
2626. Array Reduce Transformation
JavaScript
Easy
2627. Debounce
JavaScript
Medium
2628. JSON Deep Equal
JavaScript
Medium
2629. Function Composition
JavaScript
Easy
2630. Memoize II
JavaScript
Hard
2631. Group By
JavaScript
Medium
2632. Curry
JavaScript
Medium
2633. Convert Object to JSON String
JavaScript
Medium
2634. Filter Elements from Array
JavaScript
Easy
2635. Apply Transform Over Each Element in Array
JavaScript
Easy
2636. Promise Pool
JavaScript
Medium
2637. Promise Time Limit
JavaScript
Medium
2638. Count the Number of K-Free Subsets
Array
Math
Dynamic Programming
Combinatorics
Sorting
Medium
2639. Find the Width of Columns of a Grid
Array
Matrix
Easy
2640. Find the Score of All Prefixes of an Array
Array
Prefix Sum
Medium
2641. Cousins in Binary Tree II
Tree
Depth-First Search
Breadth-First Search
Hash Table
Binary Tree
Medium
2642. Design Graph With Shortest Path Calculator
Graph
Design
Shortest Path
Heap (Priority Queue)
Hard
2643. Row With Maximum Ones
Array
Matrix
Easy
2644. Find the Maximum Divisibility Score
Array
Easy
2645. Minimum Additions to Make Valid String
Stack
Greedy
String
Dynamic Programming
Medium
2646. Minimize the Total Price of the Trips
Tree
Depth-First Search
Graph
Array
Dynamic Programming
Hard
2647. Color the Triangle Red
Array
Math
Hard
2648. Generate Fibonacci Sequence
JavaScript
Easy
2649. Nested Array Generator
JavaScript
Medium
2650. Design Cancellable Function
JavaScript
Hard
2651. Calculate Delayed Arrival Time
Math
Easy
2652. Sum Multiples
Math
Easy
2653. Sliding Subarray Beauty
Array
Hash Table
Sliding Window
Medium
2654. Minimum Number of Operations to Make All Array Elements Equal to 1
Array
Math
Number Theory
Medium
2655. Find Maximal Uncovered Ranges
Array
Sorting
Medium
2656. Maximum Sum With Exactly K Elements
Greedy
Array
Easy
2657. Find the Prefix Common Array of Two Arrays
Bit Manipulation
Array
Hash Table
Medium
2658. Maximum Number of Fish in a Grid
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
2659. Make Array Empty
Greedy
Binary Indexed Tree
Segment Tree
Array
Binary Search
Ordered Set
Sorting
Hard
2660. Determine the Winner of a Bowling Game
Array
Simulation
Easy
2661. First Completely Painted Row or Column
Array
Hash Table
Matrix
Medium
2662. Minimum Cost of a Path With Special Roads
Graph
Array
Shortest Path
Heap (Priority Queue)
Medium
2663. Lexicographically Smallest Beautiful String
Greedy
String
Hard
2664. The Knight’s Tour
Array
Backtracking
Matrix
Medium
2665. Counter II
JavaScript
Easy
2666. Allow One Function Call
JavaScript
Easy
2667. Create Hello World Function
JavaScript
Easy
2670. Find the Distinct Difference Array
Array
Hash Table
Easy
2671. Frequency Tracker
Design
Hash Table
Medium
2672. Number of Adjacent Elements With the Same Color
Array
Medium
2673. Make Costs of Paths Equal in a Binary Tree
Greedy
Tree
Array
Dynamic Programming
Binary Tree
Medium
2674. Split a Circular Linked List
Linked List
Two Pointers
Medium
2675. Array of Objects to Matrix
JavaScript
Hard
2676. Throttle
JavaScript
Medium
2677. Chunk Array
JavaScript
Easy
2678. Number of Senior Citizens
Array
String
Easy
2679. Sum in a Matrix
Array
Matrix
Sorting
Simulation
Heap (Priority Queue)
Medium
2680. Maximum OR
Greedy
Bit Manipulation
Array
Prefix Sum
Medium
2681. Power of Heroes
Array
Math
Dynamic Programming
Prefix Sum
Sorting
Hard
2682. Find the Losers of the Circular Game
Array
Hash Table
Simulation
Easy
2683. Neighboring Bitwise XOR
Bit Manipulation
Array
Medium
2684. Maximum Number of Moves in a Grid
Array
Dynamic Programming
Matrix
Medium
2685. Count the Number of Complete Components
Depth-First Search
Breadth-First Search
Union Find
Graph
Medium
2689. Extract Kth Character From The Rope Tree
Tree
Depth-First Search
Binary Tree
Easy
2690. Infinite Method Object
JavaScript
Easy
2692. Make Object Immutable
JavaScript
Medium
2693. Call Function with Custom Context
JavaScript
Medium
2694. Event Emitter
JavaScript
Medium
2695. Array Wrapper
JavaScript
Easy
2696. Minimum String Length After Removing Substrings
Stack
String
Simulation
Easy
2697. Lexicographically Smallest Palindrome
Greedy
Two Pointers
String
Easy
2698. Find the Punishment Number of an Integer
Math
Backtracking
Medium
2699. Modify Graph Edge Weights
Graph
Shortest Path
Heap (Priority Queue)
Hard
2700. Differences Between Two Objects
JavaScript
Medium
2702. Minimum Operations to Make Numbers Non-positive
Array
Binary Search
Hard
2703. Return Length of Arguments Passed
JavaScript
Easy
2704. To Be Or Not To Be
JavaScript
Easy
2705. Compact Object
JavaScript
Medium
2706. Buy Two Chocolates
Greedy
Array
Sorting
Easy
2707. Extra Characters in a String
Trie
Array
Hash Table
String
Dynamic Programming
Medium
2708. Maximum Strength of a Group
Greedy
Bit Manipulation
Array
Dynamic Programming
Backtracking
Enumeration
Sorting
Medium
2709. Greatest Common Divisor Traversal
Union Find
Array
Math
Number Theory
Hard
2710. Remove Trailing Zeros From a String
String
Easy
2711. Difference of Number of Distinct Values on Diagonals
Array
Hash Table
Matrix
Medium
2712. Minimum Cost to Make All Characters Equal
Greedy
String
Dynamic Programming
Medium
2713. Maximum Strictly Increasing Cells in a Matrix
Memoization
Array
Hash Table
Binary Search
Dynamic Programming
Matrix
Ordered Set
Sorting
Hard
2714. Find Shortest Path with K Hops
Graph
Shortest Path
Heap (Priority Queue)
Hard
2715. Timeout Cancellation
JavaScript
Easy
2716. Minimize String Length
Hash Table
String
Easy
2717. Semi-Ordered Permutation
Array
Simulation
Easy
2718. Sum of Matrix After Queries
Array
Hash Table
Medium
2719. Count of Integers
Math
String
Dynamic Programming
Hard
2721. Execute Asynchronous Functions in Parallel
JavaScript
Medium
2722. Join Two Arrays by ID
JavaScript
Medium
2723. Add Two Promises
JavaScript
Easy
2724. Sort By
JavaScript
Easy
2725. Interval Cancellation
JavaScript
Easy
2726. Calculator with Method Chaining
JavaScript
Easy
2727. Is Object Empty
JavaScript
Easy
2728. Count Houses in a Circular Street
Array
Interactive
Easy
2729. Check if The Number is Fascinating
Hash Table
Math
Easy
2730. Find the Longest Semi-Repetitive Substring
String
Sliding Window
Medium
2731. Movement of Robots
Brainteaser
Array
Prefix Sum
Sorting
Medium
2732. Find a Good Subset of the Matrix
Bit Manipulation
Array
Hash Table
Matrix
Hard
2733. Neither Minimum nor Maximum
Array
Sorting
Easy
2734. Lexicographically Smallest String After Substring Operation
Greedy
String
Medium
2735. Collecting Chocolates
Array
Enumeration
Medium
2736. Maximum Sum Queries
Stack
Binary Indexed Tree
Segment Tree
Array
Binary Search
Sorting
Monotonic Stack
Hard
2737. Find the Closest Marked Node
Graph
Array
Shortest Path
Heap (Priority Queue)
Medium
2739. Total Distance Traveled
Math
Simulation
Easy
2740. Find the Value of the Partition
Array
Sorting
Medium
2741. Special Permutations
Bit Manipulation
Array
Dynamic Programming
Bitmask
Medium
2742. Painting the Walls
Array
Dynamic Programming
Hard
2743. Count Substrings Without Repeating Character
Hash Table
String
Sliding Window
Medium
2744. Find Maximum Number of String Pairs
Array
Hash Table
String
Simulation
Easy
2745. Construct the Longest New String
Greedy
Brainteaser
Math
Dynamic Programming
Medium
2746. Decremental String Concatenation
Array
String
Dynamic Programming
Medium
2747. Count Zero Request Servers
Array
Hash Table
Sorting
Sliding Window
Medium
2748. Number of Beautiful Pairs
Array
Hash Table
Math
Counting
Number Theory
Easy
2749. Minimum Operations to Make the Integer Zero
Bit Manipulation
Brainteaser
Enumeration
Medium
2750. Ways to Split Array Into Good Subarrays
Array
Math
Dynamic Programming
Medium
2751. Robot Collisions
Stack
Array
Sorting
Simulation
Hard
2753. Count Houses in a Circular Street II
Hard
2754. Bind Function to Context
JavaScript
Medium
2755. Deep Merge of Two Objects
JavaScript
Medium
2757. Generate Circular Array Values
JavaScript
Medium
2758. Next Day
JavaScript
Easy
2759. Convert JSON String to Object
JavaScript
Hard
2760. Longest Even Odd Subarray With Threshold
Array
Sliding Window
Easy
2761. Prime Pairs With Target Sum
Array
Math
Enumeration
Number Theory
Medium
2762. Continuous Subarrays
Queue
Array
Ordered Set
Sliding Window
Monotonic Queue
Heap (Priority Queue)
Medium
2763. Sum of Imbalance Numbers of All Subarrays
Array
Hash Table
Ordered Set
Hard
2764. Is Array a Preorder of Some ‌Binary Tree
Stack
Tree
Depth-First Search
Binary Tree
Medium
2765. Longest Alternating Subarray
Array
Enumeration
Easy
2766. Relocate Marbles
Array
Hash Table
Sorting
Simulation
Medium
2767. Partition String Into Minimum Beautiful Substrings
Hash Table
String
Dynamic Programming
Backtracking
Medium
2768. Number of Black Blocks
Array
Hash Table
Enumeration
Medium
2769. Find the Maximum Achievable Number
Math
Easy
2770. Maximum Number of Jumps to Reach the Last Index
Array
Dynamic Programming
Medium
2771. Longest Non-decreasing Subarray From Two Arrays
Array
Dynamic Programming
Medium
2772. Apply Operations to Make All Array Elements Equal to Zero
Array
Prefix Sum
Medium
2773. Height of Special Binary Tree
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
2774. Array Upper Bound
JavaScript
Easy
2775. Undefined to Null
JavaScript
Medium
2776. Convert Callback Based Function to Promise Based Function
JavaScript
Medium
2777. Date Range Generator
JavaScript
Medium
2778. Sum of Squares of Special Elements
Array
Enumeration
Easy
2779. Maximum Beauty of an Array After Applying Operation
Array
Binary Search
Sorting
Sliding Window
Medium
2780. Minimum Index of a Valid Split
Array
Hash Table
Sorting
Medium
2781. Length of the Longest Valid Substring
Array
Hash Table
String
Sliding Window
Hard
2782. Number of Unique Categories
Union Find
Counting
Interactive
Medium
2784. Check if Array is Good
Array
Hash Table
Sorting
Easy
2785. Sort Vowels in a String
String
Sorting
Medium
2786. Visit Array Positions to Maximize Score
Array
Dynamic Programming
Medium
2787. Ways to Express an Integer as Sum of Powers
Dynamic Programming
Medium
2788. Split Strings by Separator
Array
String
Easy
2789. Largest Element in an Array after Merge Operations
Greedy
Array
Medium
2790. Maximum Number of Groups With Increasing Length
Greedy
Array
Math
Binary Search
Sorting
Hard
2791. Count Paths That Can Form a Palindrome in a Tree
Bit Manipulation
Tree
Depth-First Search
Dynamic Programming
Bitmask
Hard
2792. Count Nodes That Are Great Enough
Tree
Depth-First Search
Divide and Conquer
Binary Tree
Hard
2794. Create Object from Two Arrays
JavaScript
Easy
2795. Parallel Execution of Promises for Individual Results Retrieval
JavaScript
Medium
2796. Repeat String
JavaScript
Easy
2797. Partial Function with Placeholders
JavaScript
Easy
2798. Number of Employees Who Met the Target
Array
Easy
2799. Count Complete Subarrays in an Array
Array
Hash Table
Sliding Window
Medium
2800. Shortest String That Contains Three Strings
Greedy
String
Enumeration
Medium
2801. Count Stepping Numbers in Range
String
Dynamic Programming
Hard
2802. Find The K-th Lucky Number
Bit Manipulation
Math
String
Medium
2803. Factorial Generator
JavaScript
Easy
2804. Array Prototype ForEach
JavaScript
Easy
2805. Custom Interval
JavaScript
Medium
2806. Account Balance After Rounded Purchase
Math
Easy
2807. Insert Greatest Common Divisors in Linked List
Linked List
Math
Number Theory
Medium
2808. Minimum Seconds to Equalize a Circular Array
Array
Hash Table
Medium
2809. Minimum Time to Make Array Sum At Most x
Array
Dynamic Programming
Sorting
Hard
2810. Faulty Keyboard
String
Simulation
Easy
2811. Check if it is Possible to Split Array
Greedy
Array
Dynamic Programming
Medium
2812. Find the Safest Path in a Grid
Breadth-First Search
Union Find
Array
Binary Search
Matrix
Heap (Priority Queue)
Medium
2813. Maximum Elegance of a K-Length Subsequence
Stack
Greedy
Array
Hash Table
Sorting
Heap (Priority Queue)
Hard
2814. Minimum Time Takes to Reach Destination Without Drowning
Breadth-First Search
Array
Matrix
Hard
2815. Max Pair Sum in an Array
Array
Hash Table
Easy
2816. Double a Number Represented as a Linked List
Stack
Linked List
Math
Medium
2817. Minimum Absolute Difference Between Elements With Constraint
Array
Binary Search
Ordered Set
Medium
2818. Apply Operations to Maximize Score
Stack
Greedy
Array
Math
Number Theory
Sorting
Monotonic Stack
Hard
2819. Minimum Relative Loss After Buying Chocolates
Array
Binary Search
Prefix Sum
Sorting
Hard
2821. Delay the Resolution of Each Promise
JavaScript
Medium
2822. Inversion of Object
JavaScript
Easy
2823. Deep Object Filter
JavaScript
Medium
2824. Count Pairs Whose Sum is Less than Target
Array
Two Pointers
Binary Search
Sorting
Easy
2825. Make String a Subsequence Using Cyclic Increments
Two Pointers
String
Medium
2826. Sorting Three Groups
Array
Binary Search
Dynamic Programming
Medium
2827. Number of Beautiful Integers in the Range
Math
Dynamic Programming
Hard
2828. Check if a String Is an Acronym of Words
Array
String
Easy
2829. Determine the Minimum Sum of a k-avoiding Array
Greedy
Math
Medium
2830. Maximize the Profit as the Salesman
Array
Hash Table
Binary Search
Dynamic Programming
Sorting
Medium
2831. Find the Longest Equal Subarray
Array
Hash Table
Binary Search
Sliding Window
Medium
2832. Maximal Range That Each Element Is Maximum in It
Stack
Array
Monotonic Stack
Medium
2833. Furthest Point From Origin
String
Counting
Easy
2834. Find the Minimum Possible Sum of a Beautiful Array
Greedy
Math
Medium
2835. Minimum Operations to Form Subsequence With Target Sum
Greedy
Bit Manipulation
Array
Hard
2836. Maximize Value of Function in a Ball Passing Game
Bit Manipulation
Array
Dynamic Programming
Hard
2838. Maximum Coins Heroes Can Collect
Array
Two Pointers
Binary Search
Prefix Sum
Sorting
Medium
2839. Check if Strings Can be Made Equal With Operations I
String
Easy
2840. Check if Strings Can be Made Equal With Operations II
Hash Table
String
Sorting
Medium
2841. Maximum Sum of Almost Unique Subarray
Array
Hash Table
Sliding Window
Medium
2842. Count K-Subsequences of a String With Maximum Beauty
Greedy
Hash Table
Math
String
Combinatorics
Hard
2843. Count Symmetric Integers
Math
Enumeration
Easy
2844. Minimum Operations to Make a Special Number
Greedy
Math
String
Enumeration
Medium
2845. Count of Interesting Subarrays
Array
Hash Table
Prefix Sum
Medium
2846. Minimum Edge Weight Equilibrium Queries in a Tree
Tree
Graph
Array
Strongly Connected Component
Hard
2847. Smallest Number With Given Digit Product
Greedy
Math
Medium
2848. Points That Intersect With Cars
Array
Hash Table
Prefix Sum
Easy
2849. Determine if a Cell Is Reachable at a Given Time
Math
Medium
2850. Minimum Moves to Spread Stones Over Grid
Breadth-First Search
Array
Dynamic Programming
Matrix
Medium
2851. String Transformation
Math
String
Dynamic Programming
String Matching
Hard
2852. Sum of Remoteness of All Cells
Depth-First Search
Breadth-First Search
Union Find
Array
Hash Table
Matrix
Medium
2855. Minimum Right Shifts to Sort the Array
Array
Easy
2856. Minimum Array Length After Pair Removals
Greedy
Array
Hash Table
Two Pointers
Binary Search
Counting
Medium
2857. Count Pairs of Points With Distance k
Bit Manipulation
Array
Hash Table
Medium
2858. Minimum Edge Reversals So Every Node Is Reachable
Depth-First Search
Breadth-First Search
Graph
Dynamic Programming
Hard
2859. Sum of Values at Indices With K Set Bits
Bit Manipulation
Array
Easy
2860. Happy Students
Array
Enumeration
Sorting
Medium
2861. Maximum Number of Alloys
Array
Binary Search
Medium
2862. Maximum Element-Sum of a Complete Subset of Indices
Array
Math
Number Theory
Hard
2863. Maximum Length of Semi-Decreasing Subarrays
Stack
Array
Sorting
Monotonic Stack
Medium
2864. Maximum Odd Binary Number
Greedy
Math
String
Easy
2865. Beautiful Towers I
Stack
Array
Monotonic Stack
Medium
2866. Beautiful Towers II
Stack
Array
Monotonic Stack
Medium
2867. Count Valid Paths in a Tree
Tree
Depth-First Search
Math
Dynamic Programming
Number Theory
Hard
2868. The Wording Game
Greedy
Array
Math
Two Pointers
String
Game Theory
Hard
2869. Minimum Operations to Collect Elements
Bit Manipulation
Array
Hash Table
Easy
2870. Minimum Number of Operations to Make Array Empty
Greedy
Array
Hash Table
Counting
Medium
2871. Split Array Into Maximum Number of Subarrays
Greedy
Bit Manipulation
Array
Medium
2872. Maximum Number of K-Divisible Components
Tree
Depth-First Search
Hard
2873. Maximum Value of an Ordered Triplet I
Array
Easy
2874. Maximum Value of an Ordered Triplet II
Array
Medium
2875. Minimum Size Subarray in Infinite Array
Array
Hash Table
Prefix Sum
Sliding Window
Medium
2876. Count Visited Nodes in a Directed Graph
Graph
Memoization
Dynamic Programming
Hard
2877. Create a DataFrame from List
Pandas
Easy
2878. Get the Size of a DataFrame
Pandas
Easy
2879. Display the First Three Rows
Pandas
Easy
2880. Select Data
Pandas
Easy
2881. Create a New Column
Pandas
Easy
2882. Drop Duplicate Rows
Pandas
Easy
2883. Drop Missing Data
Pandas
Easy
2884. Modify Columns
Pandas
Easy
2885. Rename Columns
Pandas
Easy
2886. Change Data Type
Pandas
Easy
2887. Fill Missing Data
Pandas
Easy
2888. Reshape Data Concatenate
Pandas
Easy
2889. Reshape Data Pivot
Pandas
Easy
2890. Reshape Data Melt
Pandas
Easy
2891. Method Chaining
Pandas
Easy
2892. Minimizing Array After Replacing Pairs With Their Product
Greedy
Array
Dynamic Programming
Medium
2894. Divisible and Non-divisible Sums Difference
Math
Easy
2895. Minimum Processing Time
Greedy
Array
Sorting
Medium
2896. Apply Operations to Make Two Strings Equal
String
Dynamic Programming
Medium
2897. Apply Operations on Array to Maximize Sum of Squares
Greedy
Bit Manipulation
Array
Hash Table
Hard
2898. Maximum Linear Stock Score
Array
Hash Table
Medium
2899. Last Visited Integers
Array
Simulation
Easy
2900. Longest Unequal Adjacent Groups Subsequence I
Greedy
Array
String
Dynamic Programming
Easy
2901. Longest Unequal Adjacent Groups Subsequence II
Array
String
Dynamic Programming
Medium
2902. Count of Sub-Multisets With Bounded Sum
Array
Hash Table
Dynamic Programming
Sliding Window
Hard
2903. Find Indices With Index and Value Difference I
Array
Two Pointers
Easy
2904. Shortest and Lexicographically Smallest Beautiful String
String
Sliding Window
Medium
2905. Find Indices With Index and Value Difference II
Array
Two Pointers
Medium
2906. Construct Product Matrix
Array
Matrix
Prefix Sum
Medium
2907. Maximum Profitable Triplets With Increasing Prices I
Binary Indexed Tree
Segment Tree
Array
Medium
2908. Minimum Sum of Mountain Triplets I
Array
Easy
2909. Minimum Sum of Mountain Triplets II
Array
Medium
2910. Minimum Number of Groups to Create a Valid Assignment
Greedy
Array
Hash Table
Medium
2911. Minimum Changes to Make K Semi-palindromes
Two Pointers
String
Dynamic Programming
Hard
2912. Number of Ways to Reach Destination in the Grid
Math
Dynamic Programming
Combinatorics
Hard
2913. Subarrays Distinct Element Sum of Squares I
Array
Hash Table
Easy
2914. Minimum Number of Changes to Make Binary String Beautiful
String
Medium
2915. Length of the Longest Subsequence That Sums to Target
Array
Dynamic Programming
Medium
2917. Find the K-or of an Array
Bit Manipulation
Array
Easy
2918. Minimum Equal Sum of Two Arrays After Replacing Zeros
Greedy
Array
Medium
2919. Minimum Increment Operations to Make Array Beautiful
Array
Dynamic Programming
Medium
2920. Maximum Points After Collecting Coins From All Nodes
Bit Manipulation
Tree
Depth-First Search
Memoization
Array
Dynamic Programming
Hard
2921. Maximum Profitable Triplets With Increasing Prices II
Binary Indexed Tree
Segment Tree
Array
Hard
2923. Find Champion I
Array
Matrix
Easy
2924. Find Champion II
Graph
Medium
2925. Maximum Score After Applying Operations on a Tree
Tree
Depth-First Search
Dynamic Programming
Medium
2926. Maximum Balanced Subsequence Sum
Binary Indexed Tree
Segment Tree
Array
Binary Search
Dynamic Programming
Hard
2927. Distribute Candies Among Children III
Math
Combinatorics
Hard
2928. Distribute Candies Among Children I
Math
Combinatorics
Enumeration
Easy
2929. Distribute Candies Among Children II
Math
Combinatorics
Enumeration
Medium
2930. Number of Strings Which Can Be Rearranged to Contain Substring
Math
Dynamic Programming
Combinatorics
Medium
2931. Maximum Spending After Buying Items
Greedy
Array
Matrix
Sorting
Heap (Priority Queue)
Hard
2932. Maximum Strong Pair XOR I
Bit Manipulation
Trie
Array
Hash Table
Sliding Window
Easy
2933. High-Access Employees
Array
Hash Table
String
Sorting
Medium
2934. Minimum Operations to Maximize Last Elements in Arrays
Array
Enumeration
Medium
2935. Maximum Strong Pair XOR II
Bit Manipulation
Trie
Array
Hash Table
Sliding Window
Hard
2936. Number of Equal Numbers Blocks
Array
Binary Search
Interactive
Medium
2937. Make Three Strings Equal
String
Easy
2938. Separate Black and White Balls
Greedy
Two Pointers
String
Medium
2939. Maximum Xor Product
Greedy
Bit Manipulation
Math
Medium
2940. Find Building Where Alice and Bob Can Meet
Stack
Binary Indexed Tree
Segment Tree
Array
Binary Search
Monotonic Stack
Heap (Priority Queue)
Hard
2941. Maximum GCD-Sum of a Subarray
Array
Math
Binary Search
Number Theory
Hard
2942. Find Words Containing Character
Array
String
Easy
2943. Maximize Area of Square Hole in Grid
Array
Sorting
Medium
2944. Minimum Number of Coins for Fruits
Queue
Array
Dynamic Programming
Monotonic Queue
Heap (Priority Queue)
Medium
2945. Find Maximum Non-decreasing Array Length
Stack
Queue
Array
Binary Search
Dynamic Programming
Monotonic Queue
Monotonic Stack
Hard
2946. Matrix Similarity After Cyclic Shifts
Array
Math
Matrix
Simulation
Easy
2947. Count Beautiful Substrings I
Hash Table
Math
String
Enumeration
Number Theory
Prefix Sum
Medium
2948. Make Lexicographically Smallest Array by Swapping Elements
Union Find
Array
Sorting
Medium
2949. Count Beautiful Substrings II
Hash Table
Math
String
Number Theory
Prefix Sum
Hard
2950. Number of Divisible Substrings
Hash Table
String
Counting
Prefix Sum
Medium
2951. Find the Peaks
Array
Enumeration
Easy
2952. Minimum Number of Coins to be Added
Greedy
Array
Sorting
Medium
2953. Count Complete Substrings
Hash Table
String
Sliding Window
Hard
2954. Count the Number of Infection Sequences
Array
Math
Combinatorics
Hard
2955. Number of Same-End Substrings
Array
Hash Table
String
Counting
Prefix Sum
Medium
2956. Find Common Elements Between Two Arrays
Array
Hash Table
Easy
2957. Remove Adjacent Almost-Equal Characters
Greedy
String
Dynamic Programming
Medium
2958. Length of Longest Subarray With at Most K Frequency
Array
Hash Table
Sliding Window
Medium
2959. Number of Possible Sets of Closing Branches
Bit Manipulation
Graph
Enumeration
Shortest Path
Heap (Priority Queue)
Hard
2960. Count Tested Devices After Test Operations
Array
Counting
Simulation
Easy
2961. Double Modular Exponentiation
Array
Math
Simulation
Medium
2962. Count Subarrays Where Max Element Appears at Least K Times
Array
Sliding Window
Medium
2963. Count the Number of Good Partitions
Array
Hash Table
Math
Combinatorics
Hard
2964. Number of Divisible Triplet Sums
Array
Hash Table
Medium
2965. Find Missing and Repeated Values
Array
Hash Table
Math
Matrix
Easy
2966. Divide Array Into Arrays With Max Difference
Greedy
Array
Sorting
Medium
2967. Minimum Cost to Make Array Equalindromic
Greedy
Array
Math
Binary Search
Sorting
Medium
2968. Apply Operations to Maximize Frequency Score
Array
Binary Search
Prefix Sum
Sorting
Sliding Window
Hard
2969. Minimum Number of Coins for Fruits II
Queue
Array
Dynamic Programming
Monotonic Queue
Heap (Priority Queue)
Hard
2970. Count the Number of Incremovable Subarrays I
Array
Two Pointers
Binary Search
Enumeration
Easy
2971. Find Polygon With the Largest Perimeter
Greedy
Array
Prefix Sum
Sorting
Medium
2972. Count the Number of Incremovable Subarrays II
Array
Two Pointers
Binary Search
Hard
2973. Find Number of Coins to Place in Tree Nodes
Tree
Depth-First Search
Dynamic Programming
Sorting
Heap (Priority Queue)
Hard
2974. Minimum Number Game
Array
Sorting
Simulation
Heap (Priority Queue)
Easy
2975. Maximum Square Area by Removing Fences From a Field
Array
Hash Table
Enumeration
Medium
2976. Minimum Cost to Convert String I
Graph
Array
String
Shortest Path
Medium
2977. Minimum Cost to Convert String II
Graph
Trie
Array
String
Dynamic Programming
Shortest Path
Hard
2979. Most Expensive Item That Can Not Be Bought
Math
Dynamic Programming
Number Theory
Medium
2980. Check if Bitwise OR Has Trailing Zeros
Bit Manipulation
Array
Easy
2981. Find Longest Special Substring That Occurs Thrice I
Hash Table
String
Binary Search
Counting
Sliding Window
Medium
2982. Find Longest Special Substring That Occurs Thrice II
Hash Table
String
Binary Search
Counting
Sliding Window
Medium
2983. Palindrome Rearrangement Queries
Hash Table
String
Prefix Sum
Hard
2992. Number of Self-Divisible Permutations
Bit Manipulation
Array
Math
Dynamic Programming
Backtracking
Bitmask
Number Theory
Medium
2996. Smallest Missing Integer Greater Than Sequential Prefix Sum
Array
Hash Table
Sorting
Easy
2997. Minimum Number of Operations to Make Array XOR Equal to K
Bit Manipulation
Array
Medium
2998. Minimum Number of Operations to Make X and Y Equal
Breadth-First Search
Memoization
Dynamic Programming
Medium
2999. Count the Number of Powerful Integers
Math
String
Dynamic Programming
Hard
3000. Maximum Area of Longest Diagonal Rectangle
Array
Easy
3001. Minimum Moves to Capture The Queen
Math
Enumeration
Medium
3002. Maximum Size of a Set After Removals
Greedy
Array
Hash Table
Medium
3003. Maximize the Number of Partitions After Operations
Bit Manipulation
String
Dynamic Programming
Bitmask
Hard
3004. Maximum Subtree of the Same Color
Tree
Depth-First Search
Array
Dynamic Programming
Medium
3005. Count Elements With Maximum Frequency
Array
Hash Table
Counting
Easy
3006. Find Beautiful Indices in the Given Array I
Two Pointers
String
Binary Search
String Matching
Hash Function
Rolling Hash
Medium
3007. Maximum Number That Sum of the Prices Is Less Than or Equal to K
Bit Manipulation
Binary Search
Dynamic Programming
Medium
3008. Find Beautiful Indices in the Given Array II
Two Pointers
String
Binary Search
String Matching
Hash Function
Rolling Hash
Hard
3009. Maximum Number of Intersections on the Chart
Binary Indexed Tree
Geometry
Array
Math
Hard
3010. Divide an Array Into Subarrays With Minimum Cost I
Array
Enumeration
Sorting
Easy
3011. Find if Array Can Be Sorted
Bit Manipulation
Array
Sorting
Medium
3012. Minimize Length of Array Using Operations
Greedy
Array
Math
Number Theory
Medium
3013. Divide an Array Into Subarrays With Minimum Cost II
Array
Hash Table
Sliding Window
Heap (Priority Queue)
Hard
3014. Minimum Number of Pushes to Type Word I
Greedy
Math
String
Easy
3015. Count the Number of Houses at a Certain Distance I
Breadth-First Search
Graph
Prefix Sum
Medium
3016. Minimum Number of Pushes to Type Word II
Greedy
Hash Table
String
Counting
Sorting
Medium
3017. Count the Number of Houses at a Certain Distance II
Graph
Prefix Sum
Hard
3018. Maximum Number of Removal Queries That Can Be Processed I
Array
Dynamic Programming
Hard
3019. Number of Changing Keys
String
Easy
3020. Find the Maximum Number of Elements in Subset
Array
Hash Table
Enumeration
Medium
3021. Alice and Bob Playing Flower Game
Math
Medium
3022. Minimize OR of Remaining Elements Using Operations
Greedy
Bit Manipulation
Array
Hard
3023. Find Pattern in Infinite Stream I
Array
String Matching
Sliding Window
Hash Function
Rolling Hash
Medium
3024. Type of Triangle
Array
Math
Sorting
Easy
3025. Find the Number of Ways to Place People I
Geometry
Array
Math
Enumeration
Sorting
Medium
3026. Maximum Good Subarray Sum
Array
Hash Table
Prefix Sum
Medium
3027. Find the Number of Ways to Place People II
Geometry
Array
Math
Enumeration
Sorting
Hard
3028. Ant on the Boundary
Array
Prefix Sum
Simulation
Easy
3029. Minimum Time to Revert Word to Initial State I
String
String Matching
Hash Function
Rolling Hash
Medium
3030. Find the Grid of Region Average
Array
Matrix
Medium
3031. Minimum Time to Revert Word to Initial State II
String
String Matching
Hash Function
Rolling Hash
Hard
3032. Count Numbers With Unique Digits II
Hash Table
Math
Dynamic Programming
Easy
3033. Modify the Matrix
Array
Matrix
Easy
3034. Number of Subarrays That Match a Pattern I
Array
String Matching
Hash Function
Rolling Hash
Medium
3035. Maximum Palindromes After Operations
Greedy
Array
Hash Table
String
Counting
Sorting
Medium
3036. Number of Subarrays That Match a Pattern II
Array
String Matching
Hash Function
Rolling Hash
Hard
3038. Maximum Number of Operations With the Same Score I
Array
Simulation
Easy
3039. Apply Operations to Make String Empty
Array
Hash Table
Counting
Sorting
Medium
3040. Maximum Number of Operations With the Same Score II
Memoization
Array
Dynamic Programming
Medium
3042. Count Prefix and Suffix Pairs I
Trie
Array
String
String Matching
Hash Function
Rolling Hash
Easy
3043. Find the Length of the Longest Common Prefix
Trie
Array
Hash Table
String
Medium
3044. Most Frequent Prime
Array
Hash Table
Math
Counting
Enumeration
Matrix
Number Theory
Medium
3045. Count Prefix and Suffix Pairs II
Trie
Array
String
String Matching
Hash Function
Rolling Hash
Hard
3046. Split the Array
Array
Hash Table
Counting
Easy
3047. Find the Largest Area of Square Inside Two Rectangles
Geometry
Array
Math
Medium
3048. Earliest Second to Mark Indices I
Array
Binary Search
Medium
3062. Winner of the Linked List Game
Linked List
Easy
3063. Linked List Frequency
Hash Table
Linked List
Counting
Easy
3064. Guess the Number Using Bitwise Questions I
Bit Manipulation
Interactive
Medium
3065. Minimum Operations to Exceed Threshold Value I
Array
Easy
3066. Minimum Operations to Exceed Threshold Value II
Array
Simulation
Heap (Priority Queue)
Medium
3067. Count Pairs of Connectable Servers in a Weighted Tree Network
Tree
Depth-First Search
Array
Medium
3068. Find the Maximum Sum of Node Values
Greedy
Bit Manipulation
Tree
Array
Dynamic Programming
Sorting
Hard
3069. Distribute Elements Into Two Arrays I
Array
Simulation
Easy
3070. Count Submatrices with Top-Left Element and Sum Less Than k
Array
Matrix
Prefix Sum
Medium
3071. Minimum Operations to Write the Letter Y on a Grid
Array
Hash Table
Counting
Matrix
Medium
3072. Distribute Elements Into Two Arrays II
Binary Indexed Tree
Segment Tree
Array
Simulation
Hard
3073. Maximum Increasing Triplet Value
Array
Ordered Set
Medium
3074. Apple Redistribution into Boxes
Greedy
Array
Sorting
Easy
3075. Maximize Happiness of Selected Children
Greedy
Array
Sorting
Medium
3076. Shortest Uncommon Substring in an Array
Trie
Array
Hash Table
String
Medium
3077. Maximum Strength of K Disjoint Subarrays
Array
Dynamic Programming
Prefix Sum
Hard
3078. Match Alphanumerical Pattern in Matrix I
Array
Hash Table
String
Matrix
Medium
3079. Find the Sum of Encrypted Integers
Array
Math
Easy
3080. Mark Elements on Array by Performing Queries
Array
Hash Table
Sorting
Simulation
Heap (Priority Queue)
Medium
3081. Replace Question Marks in String to Minimize Its Value
Greedy
Hash Table
String
Counting
Sorting
Heap (Priority Queue)
Medium
3082. Find the Sum of the Power of All Subsequences
Array
Dynamic Programming
Hard
3083. Existence of a Substring in a String and Its Reverse
Hash Table
String
Easy
3084. Count Substrings Starting and Ending with Given Character
Math
String
Counting
Medium
3085. Minimum Deletions to Make String K-Special
Greedy
Hash Table
String
Counting
Sorting
Medium
3086. Minimum Moves to Pick K Ones
Greedy
Array
Prefix Sum
Sliding Window
Hard
3088. Make String Anti-palindrome
Greedy
String
Counting Sort
Sorting
Hard
3090. Maximum Length Substring With Two Occurrences
Hash Table
String
Sliding Window
Easy
3091. Apply Operations to Make Sum of Array Greater Than or Equal to k
Greedy
Math
Enumeration
Medium
3092. Most Frequent IDs
Array
Hash Table
Ordered Set
Heap (Priority Queue)
Medium
3093. Longest Common Suffix Queries
Trie
Array
String
Hard
3094. Guess the Number Using Bitwise Questions II
Bit Manipulation
Interactive
Medium
3095. Shortest Subarray With OR at Least K I
Bit Manipulation
Array
Sliding Window
Easy
3096. Minimum Levels to Gain More Points
Array
Prefix Sum
Medium
3097. Shortest Subarray With OR at Least K II
Bit Manipulation
Array
Sliding Window
Medium
3098. Find the Sum of Subsequence Powers
Array
Dynamic Programming
Sorting
Hard
3099. Harshad Number
Math
Easy
3100. Water Bottles II
Math
Simulation
Medium
3101. Count Alternating Subarrays
Array
Math
Medium
3102. Minimize Manhattan Distances
Geometry
Array
Math
Ordered Set
Sorting
Hard
3103. Find Trending Hashtags II
Database
Hard
3104. Find Longest Self-Contained Substring
Hash Table
String
Binary Search
Prefix Sum
Hard
3105. Longest Strictly Increasing or Strictly Decreasing Subarray
Array
Easy
3106. Lexicographically Smallest String After Operations With Constraint
Greedy
String
Medium
3107. Minimum Operations to Make Median of Array Equal to K
Greedy
Array
Sorting
Medium
3108. Minimum Cost Walk in Weighted Graph
Bit Manipulation
Union Find
Graph
Array
Hard
3109. Find the Index of Permutation
Binary Indexed Tree
Segment Tree
Array
Binary Search
Divide and Conquer
Ordered Set
Merge Sort
Medium
3110. Score of a String
String
Easy
3111. Minimum Rectangles to Cover Points
Greedy
Array
Sorting
Medium
3112. Minimum Time to Visit Disappearing Nodes
Graph
Array
Shortest Path
Heap (Priority Queue)
Medium
3113. Find the Number of Subarrays Where Boundary Elements Are Maximum
Stack
Array
Binary Search
Monotonic Stack
Hard
3114. Latest Time You Can Obtain After Replacing Characters
String
Enumeration
Easy
3115. Maximum Prime Difference
Array
Math
Number Theory
Medium
3116. Kth Smallest Amount With Single Denomination Combination
Bit Manipulation
Array
Math
Binary Search
Combinatorics
Number Theory
Hard
3117. Minimum Sum of Values by Dividing Array
Bit Manipulation
Segment Tree
Queue
Array
Binary Search
Dynamic Programming
Hard
3119. Maximum Number of Potholes That Can Be Fixed
Greedy
String
Sorting
Medium
3120. Count the Number of Special Characters I
Hash Table
String
Easy
3121. Count the Number of Special Characters II
Hash Table
String
Medium
3122. Minimum Number of Operations to Satisfy Conditions
Array
Dynamic Programming
Matrix
Medium
3123. Find Edges in Shortest Paths
Depth-First Search
Breadth-First Search
Graph
Shortest Path
Heap (Priority Queue)
Hard
3125. Maximum Number That Makes Result of Bitwise AND Zero
Greedy
String
Sorting
Medium
3127. Make a Square with the Same Color
Array
Enumeration
Matrix
Easy
3128. Right Triangles
Array
Hash Table
Math
Combinatorics
Counting
Medium
3129. Find All Possible Stable Binary Arrays I
Dynamic Programming
Prefix Sum
Medium
3130. Find All Possible Stable Binary Arrays II
Dynamic Programming
Prefix Sum
Hard
3131. Find the Integer Added to Array I
Array
Easy
3132. Find the Integer Added to Array II
Array
Two Pointers
Enumeration
Sorting
Medium
3133. Minimum Array End
Bit Manipulation
Medium
3134. Find the Median of the Uniqueness Array
Array
Hash Table
Binary Search
Sliding Window
Hard
3135. Equalize Strings by Adding or Removing Characters at Ends
String
Binary Search
Dynamic Programming
Sliding Window
Hash Function
Medium
3136. Valid Word
String
Easy
3137. Minimum Number of Operations to Make Word K-Periodic
Hash Table
String
Counting
Medium
3138. Minimum Length of Anagram Concatenation
Hash Table
String
Counting
Medium
3141. Maximum Hamming Distances
Bit Manipulation
Breadth-First Search
Array
Hard
3142. Check if Grid Satisfies Conditions
Array
Matrix
Easy
3143. Maximum Points Inside the Square
Array
Hash Table
String
Binary Search
Sorting
Medium
3144. Minimum Substring Partition of Equal Character Frequency
Hash Table
String
Dynamic Programming
Counting
Medium
3145. Find Products of Elements of Big Array
Bit Manipulation
Array
Binary Search
Hard
3146. Permutation Difference between Two Strings
Hash Table
String
Easy
3147. Taking Maximum Energy From the Mystic Dungeon
Array
Prefix Sum
Medium
3148. Maximum Difference Score in a Grid
Array
Dynamic Programming
Matrix
Medium
3149. Find the Minimum Cost Array Permutation
Bit Manipulation
Array
Dynamic Programming
Bitmask
Hard
3151. Special Array I
Array
Easy
3152. Special Array II
Array
Binary Search
Prefix Sum
Medium
3153. Sum of Digit Differences of All Pairs
Array
Hash Table
Math
Counting
Medium
3154. Find Number of Ways to Reach the K-th Stair
Bit Manipulation
Memoization
Math
Dynamic Programming
Combinatorics
Hard
3155. Maximum Number of Upgradable Servers
Array
Math
Binary Search
Medium
3157. Find the Level of Tree with Minimum Sum
Tree
Depth-First Search
Breadth-First Search
Binary Tree
Medium
3158. Find the XOR of Numbers Which Appear Twice
Bit Manipulation
Array
Hash Table
Easy
3159. Find Occurrences of an Element in an Array
Array
Hash Table
Medium
3160. Find the Number of Distinct Colors Among the Balls
Array
Hash Table
Simulation
Medium
3162. Find the Number of Good Pairs I
Array
Hash Table
Easy
3163. String Compression III
String
Medium
3164. Find the Number of Good Pairs II
Array
Hash Table
Medium
3165. Maximum Sum of Subsequence With Non-adjacent Elements
Segment Tree
Array
Divide and Conquer
Dynamic Programming
Hard
3167. Better Compression of String
Hash Table
String
Counting
Sorting
Medium
3168. Minimum Number of Chairs in a Waiting Room
String
Simulation
Easy
3169. Count Days Without Meetings
Array
Sorting
Medium
3170. Lexicographically Minimum String After Removing Stars
Stack
Greedy
Hash Table
String
Heap (Priority Queue)
Medium
3171. Find Subarray With Bitwise OR Closest to K
Bit Manipulation
Segment Tree
Array
Binary Search
Hard
3173. Bitwise OR of Adjacent Elements
Bit Manipulation
Array
Easy
3174. Clear Digits
Stack
String
Simulation
Easy
3175. Find The First Player to win K Games in a Row
Array
Simulation
Medium
3176. Find the Maximum Length of a Good Subsequence I
Array
Hash Table
Dynamic Programming
Medium
3177. Find the Maximum Length of a Good Subsequence II
Array
Hash Table
Dynamic Programming
Hard
3178. Find the Child Who Has the Ball After K Seconds
Math
Simulation
Easy
3179. Find the N-th Value After K Seconds
Array
Math
Combinatorics
Prefix Sum
Simulation
Medium
3180. Maximum Total Reward Using Operations I
Array
Dynamic Programming
Medium
3181. Maximum Total Reward Using Operations II
Bit Manipulation
Array
Dynamic Programming
Hard
3183. The Number of Ways to Make the Sum
Array
Dynamic Programming
Medium
3184. Count Pairs That Form a Complete Day I
Array
Hash Table
Counting
Easy
3185. Count Pairs That Form a Complete Day II
Array
Hash Table
Counting
Medium
3186. Maximum Total Damage With Spell Casting
Array
Hash Table
Two Pointers
Binary Search
Dynamic Programming
Counting
Sorting
Medium
3187. Peaks in Array
Binary Indexed Tree
Segment Tree
Array
Hard
3189. Minimum Moves to Get a Peaceful Board
Greedy
Array
Counting Sort
Sorting
Medium
3190. Find Minimum Operations to Make All Elements Divisible by Three
Array
Math
Easy
3191. Minimum Operations to Make Binary Array Elements Equal to One I
Bit Manipulation
Queue
Array
Prefix Sum
Sliding Window
Medium
3192. Minimum Operations to Make Binary Array Elements Equal to One II
Greedy
Array
Dynamic Programming
Medium
3193. Count the Number of Inversions
Array
Dynamic Programming
Hard
3194. Minimum Average of Smallest and Largest Elements
Array
Two Pointers
Sorting
Easy
3195. Find the Minimum Area to Cover All Ones I
Array
Matrix
Medium
3196. Maximize Total Cost of Alternating Subarrays
Array
Dynamic Programming
Medium
3197. Find the Minimum Area to Cover All Ones II
Array
Enumeration
Matrix
Hard
3199. Count Triplets with Even XOR Set Bits I
Bit Manipulation
Array
Easy
3200. Maximum Height of a Triangle
Array
Enumeration
Easy
3201. Find the Maximum Length of Valid Subsequence I
Array
Dynamic Programming
Medium
3202. Find the Maximum Length of Valid Subsequence II
Array
Dynamic Programming
Medium
3203. Find Minimum Diameter After Merging Two Trees
Tree
Depth-First Search
Breadth-First Search
Graph
Hard
3205. Maximum Array Hopping Score I
Stack
Greedy
Array
Dynamic Programming
Monotonic Stack
Medium
3206. Alternating Groups I
Array
Sliding Window
Easy
3207. Maximum Points After Enemy Battles
Greedy
Array
Medium
3208. Alternating Groups II
Array
Sliding Window
Medium
3209. Number of Subarrays With AND Value of K
Bit Manipulation
Segment Tree
Array
Binary Search
Hard
3210. Find the Encrypted String
String
Easy
3211. Generate Binary Strings Without Adjacent Zeros
Bit Manipulation
String
Backtracking
Medium
3212. Count Submatrices With Equal Frequency of X and Y
Array
Matrix
Prefix Sum
Medium
3213. Construct String with Minimum Cost
Array
String
Dynamic Programming
Suffix Array
Hard
3215. Count Triplets with Even XOR Set Bits II
Bit Manipulation
Array
Medium
3216. Lexicographically Smallest String After a Swap
Greedy
String
Easy
3217. Delete Nodes From Linked List Present in Array
Array
Hash Table
Linked List
Medium
3218. Minimum Cost for Cutting Cake I
Greedy
Array
Dynamic Programming
Sorting
Medium
3219. Minimum Cost for Cutting Cake II
Greedy
Array
Sorting
Hard
3221. Maximum Array Hopping Score II
Stack
Greedy
Array
Monotonic Stack
Medium
3222. Find the Winning Player in Coin Game
Math
Game Theory
Simulation
Easy
3223. Minimum Length of String After Operations
Hash Table
String
Counting
Medium
3224. Minimum Array Changes to Make Differences Equal
Array
Hash Table
Prefix Sum
Medium
3226. Number of Bit Changes to Make Two Integers Equal
Bit Manipulation
Easy
3227. Vowels Game in a String
Brainteaser
Math
String
Game Theory
Medium
3228. Maximum Number of Operations to Move Ones to the End
Greedy
String
Counting
Medium
3229. Minimum Operations to Make Array Equal to Target
Stack
Greedy
Array
Dynamic Programming
Monotonic Stack
Hard
3231. Minimum Number of Increasing Subsequence to Be Removed
Array
Binary Search
Hard
3232. Find if Digit Game Can Be Won
Array
Math
Easy
3233. Find the Count of Numbers Which Are Not Special
Array
Math
Number Theory
Medium
3235. Check if the Rectangle Corner Is Reachable
Depth-First Search
Breadth-First Search
Union Find
Geometry
Array
Math
Hard
3237. Alt and Tab Simulation
Array
Hash Table
Simulation
Medium
3238. Find the Number of Winning Players
Array
Hash Table
Counting
Easy
3239. Minimum Number of Flips to Make Binary Grid Palindromic I
Array
Two Pointers
Matrix
Medium
3240. Minimum Number of Flips to Make Binary Grid Palindromic II
Array
Two Pointers
Matrix
Medium
3242. Design Neighbor Sum Service
Design
Array
Hash Table
Matrix
Simulation
Easy
3243. Shortest Distance After Road Addition Queries I
Breadth-First Search
Graph
Array
Medium
3244. Shortest Distance After Road Addition Queries II
Greedy
Graph
Array
Ordered Set
Hard
3247. Number of Subsequences with Odd Sum
Array
Math
Dynamic Programming
Combinatorics
Medium
3248. Snake in Matrix
Array
String
Simulation
Easy
3249. Count the Number of Good Nodes
Tree
Depth-First Search
Medium
3250. Find the Count of Monotonic Pairs I
Array
Math
Dynamic Programming
Combinatorics
Prefix Sum
Hard
3251. Find the Count of Monotonic Pairs II
Array
Math
Dynamic Programming
Combinatorics
Prefix Sum
Hard
3253. Construct String with Minimum Cost (Easy)
Medium
3254. Find the Power of K-Size Subarrays I
Array
Sliding Window
Medium
3255. Find the Power of K-Size Subarrays II
Array
Sliding Window
Medium
3258. Count Substrings That Satisfy K-Constraint I
String
Sliding Window
Easy
3259. Maximum Energy Boost From Two Drinks
Array
Dynamic Programming
Medium
3261. Count Substrings That Satisfy K-Constraint II
Array
String
Binary Search
Prefix Sum
Sliding Window
Hard
3263. Convert Doubly Linked List to Array I
Array
Linked List
Doubly-Linked List
Easy
3264. Final Array State After K Multiplication Operations I
Array
Math
Simulation
Heap (Priority Queue)
Easy
3265. Count Almost Equal Pairs I
Array
Hash Table
Counting
Enumeration
Sorting
Medium
3266. Final Array State After K Multiplication Operations II
Array
Simulation
Heap (Priority Queue)
Hard
3267. Count Almost Equal Pairs II
Array
Hash Table
Counting
Enumeration
Sorting
Hard
3269. Constructing Two Increasing Arrays
Array
Dynamic Programming
Hard
3270. Find the Key of the Numbers
Math
Easy
3271. Hash Divided String
String
Simulation
Medium
3272. Find the Count of Good Integers
Hash Table
Math
Combinatorics
Enumeration
Hard
3274. Check if Two Chessboard Squares Have the Same Color
Math
String
Easy
3275. K-th Nearest Obstacle Queries
Array
Heap (Priority Queue)
Medium
3276. Select Cells in Grid With Maximum Score
Bit Manipulation
Array
Dynamic Programming
Bitmask
Matrix
Hard
3277. Maximum XOR Score Subarray Queries
Array
Dynamic Programming
Hard
3279. Maximum Total Area Occupied by Pistons
Array
Hash Table
String
Counting
Prefix Sum
Simulation
Hard
3280. Convert Date to Binary
Math
String
Easy
3281. Maximize Score of Numbers in Ranges
Greedy
Array
Binary Search
Sorting
Medium
3282. Reach End of Array With Max Score
Greedy
Array
Medium
3283. Maximum Number of Moves to Kill All Pawns
Bit Manipulation
Breadth-First Search
Array
Math
Bitmask
Game Theory
Hard
3284. Sum of Consecutive Subarrays
Array
Two Pointers
Dynamic Programming
Medium
3285. Find Indices of Stable Mountains
Array
Easy
3286. Find a Safe Walk Through a Grid
Breadth-First Search
Graph
Array
Matrix
Shortest Path
Heap (Priority Queue)
Medium
3287. Find the Maximum Sequence Value of Array
Bit Manipulation
Array
Dynamic Programming
Hard
3289. The Two Sneaky Numbers of Digitville
Array
Hash Table
Math
Easy
3290. Maximum Multiplication Score
Array
Dynamic Programming
Medium
3291. Minimum Number of Valid Strings to Form Target I
Trie
Segment Tree
Array
String
Binary Search
Dynamic Programming
String Matching
Hash Function
Rolling Hash
Medium
3292. Minimum Number of Valid Strings to Form Target II
Segment Tree
Array
String
Binary Search
Dynamic Programming
String Matching
Hash Function
Rolling Hash
Hard
3294. Convert Doubly Linked List to Array II
Array
Linked List
Doubly-Linked List
Medium
3295. Report Spam Message
Array
Hash Table
String
Medium
3296. Minimum Number of Seconds to Make Mountain Height Zero
Greedy
Array
Math
Binary Search
Heap (Priority Queue)
Medium
3297. Count Substrings That Can Be Rearranged to Contain a String I
Hash Table
String
Sliding Window
Medium
3298. Count Substrings That Can Be Rearranged to Contain a String II
Hash Table
String
Sliding Window
Hard
3299. Sum of Consecutive Subsequences
Array
Hash Table
Dynamic Programming
Hard
3300. Minimum Element After Replacement With Digit Sum
Array
Math
Easy
3301. Maximize the Total Height of Unique Towers
Greedy
Array
Sorting
Medium
3304. Find the K-th Character in String Game I
Bit Manipulation
Recursion
Math
Simulation
Easy
3305. Count of Substrings Containing Every Vowel and K Consonants I
Hash Table
String
Sliding Window
Medium
3306. Count of Substrings Containing Every Vowel and K Consonants II
Hash Table
String
Sliding Window
Medium
3307. Find the K-th Character in String Game II
Bit Manipulation
Recursion
Math
Hard
3309. Maximum Possible Number by Binary Concatenation
Bit Manipulation
Array
Enumeration
Medium
3310. Remove Methods From Project
Depth-First Search
Breadth-First Search
Graph
Medium
3311. Construct 2D Grid Matching Graph Layout
Graph
Array
Hash Table
Matrix
Hard
3312. Sorted GCD Pair Queries
Array
Hash Table
Math
Binary Search
Combinatorics
Counting
Number Theory
Prefix Sum
Hard
3313. Find the Last Marked Nodes in Tree
Tree
Depth-First Search
Hard
3314. Construct the Minimum Bitwise Array I
Bit Manipulation
Array
Easy
3315. Construct the Minimum Bitwise Array II
Bit Manipulation
Array
Medium
3316. Find Maximum Removals From Source String
Array
Hash Table
Two Pointers
String
Dynamic Programming
Medium
3317. Find the Number of Possible Ways for an Event
Math
Dynamic Programming
Combinatorics
Hard
3318. Find X-Sum of All K-Long Subarrays I
Array
Hash Table
Sliding Window
Heap (Priority Queue)
Easy
3319. K-th Largest Perfect Subtree Size in Binary Tree
Tree
Depth-First Search
Binary Tree
Sorting
Medium
3320. Count The Number of Winning Sequences
String
Dynamic Programming
Hard
3321. Find X-Sum of All K-Long Subarrays II
Array
Hash Table
Sliding Window
Heap (Priority Queue)
Hard
3323. Minimize Connected Groups by Inserting Interval
Array
Binary Search
Sorting
Sliding Window
Medium
3324. Find the Sequence of Strings Appeared on the Screen
String
Simulation
Medium
3325. Count Substrings With K-Frequency Characters I
Hash Table
String
Sliding Window
Medium
3326. Minimum Division Operations to Make Array Non Decreasing
Greedy
Array
Math
Number Theory
Medium
3327. Check if DFS Strings Are Palindromes
Tree
Depth-First Search
Array
Hash Table
String
Hash Function
Hard
3329. Count Substrings With K-Frequency Characters II
Hash Table
String
Sliding Window
Hard
3330. Find the Original Typed String I
String
Easy
3331. Find Subtree Sizes After Changes
Tree
Depth-First Search
Array
Hash Table
String
Medium
3332. Maximum Points Tourist Can Earn
Array
Dynamic Programming
Matrix
Medium
3333. Find the Original Typed String II
String
Dynamic Programming
Prefix Sum
Hard
3334. Find the Maximum Factor Score of Array
Array
Math
Number Theory
Medium
3335. Total Characters in String After Transformations I
Hash Table
Math
String
Dynamic Programming
Counting
Medium
3337. Total Characters in String After Transformations II
Hash Table
Math
String
Dynamic Programming
Counting
Hard
3339. Find the Number of K-Even Arrays
Dynamic Programming
Medium
3340. Check Balanced String
String
Easy
3341. Find Minimum Time to Reach Last Room I
Graph
Array
Matrix
Shortest Path
Heap (Priority Queue)
Medium
3342. Find Minimum Time to Reach Last Room II
Graph
Array
Matrix
Shortest Path
Heap (Priority Queue)
Medium
3343. Count Number of Balanced Permutations
Math
String
Dynamic Programming
Combinatorics
Hard
3344. Maximum Sized Array
Bit Manipulation
Binary Search
Medium
3345. Smallest Divisible Digit Product I
Math
Enumeration
Easy
3346. Maximum Frequency of an Element After Performing Operations I
Array
Binary Search
Prefix Sum
Sorting
Sliding Window
Medium
3347. Maximum Frequency of an Element After Performing Operations II
Array
Binary Search
Prefix Sum
Sorting
Sliding Window
Hard
3349. Adjacent Increasing Subarrays Detection I
Array
Easy
3350. Adjacent Increasing Subarrays Detection II
Array
Binary Search
Medium
3351. Sum of Good Subsequences
Array
Hash Table
Dynamic Programming
Hard
3353. Minimum Total Operations
Array
Easy
3354. Make Array Elements Equal to Zero
Array
Prefix Sum
Simulation
Easy
3355. Zero Array Transformation I
Array
Prefix Sum
Medium
3356. Zero Array Transformation II
Array
Binary Search
Prefix Sum
Medium
3360. Stone Removal Game
Math
Simulation
Easy
3361. Shift Distance Between Two Strings
Array
String
Prefix Sum
Medium
3362. Zero Array Transformation III
Greedy
Array
Prefix Sum
Sorting
Heap (Priority Queue)
Medium
3363. Find the Maximum Number of Fruits Collected
Array
Dynamic Programming
Matrix
Hard
3364. Minimum Positive Sum Subarray
Array
Prefix Sum
Sliding Window
Easy
3365. Rearrange K Substrings to Form Target String
Hash Table
String
Sorting
Medium
3366. Minimum Array Sum
Array
Dynamic Programming
Medium
3367. Maximize Sum of Weights after Edge Removals
Tree
Depth-First Search
Dynamic Programming
Hard
3369. Design an Array Statistics Tracker
Design
Queue
Hash Table
Binary Search
Data Stream
Ordered Set
Heap (Priority Queue)
Hard
3370. Smallest Number With All Set Bits
Bit Manipulation
Math
Easy
3371. Identify the Largest Outlier in an Array
Array
Hash Table
Counting
Enumeration
Medium
3372. Maximize the Number of Target Nodes After Connecting Trees I
Tree
Depth-First Search
Breadth-First Search
Medium
3373. Maximize the Number of Target Nodes After Connecting Trees II
Tree
Depth-First Search
Breadth-First Search
Hard
3374. First Letter Capitalization II
Database
Hard
3375. Minimum Operations to Make Array Values Equal to K
Array
Hash Table
Easy
3376. Minimum Time to Break Locks I
Bit Manipulation
Depth-First Search
Array
Dynamic Programming
Backtracking
Bitmask
Medium
3377. Digit Operations to Make Two Integers Equal
Graph
Math
Number Theory
Shortest Path
Heap (Priority Queue)
Medium
3378. Count Connected Components in LCM Graph
Union Find
Array
Hash Table
Math
Number Theory
Hard
3379. Transformed Array
Array
Simulation
Easy
3380. Maximum Area Rectangle With Point Constraints I
Binary Indexed Tree
Segment Tree
Geometry
Array
Math
Enumeration
Sorting
Medium
3381. Maximum Subarray Sum With Length Divisible by K
Array
Hash Table
Prefix Sum
Medium
3383. Minimum Runes to Add to Cast Spell
Depth-First Search
Breadth-First Search
Union Find
Graph
Topological Sort
Array
Hard
3385. Minimum Time to Break Locks II
Depth-First Search
Graph
Array
Hard
3386. Button with Longest Push Time
Array
Easy
3387. Maximize Amount After Two Days of Conversions
Depth-First Search
Breadth-First Search
Graph
Array
String
Medium
3388. Count Beautiful Splits in an Array
Array
Dynamic Programming
Medium
3391. Design a 3D Binary Matrix with Efficient Layer Tracking
Design
Array
Hash Table
Matrix
Ordered Set
Heap (Priority Queue)
Medium
3392. Count Subarrays of Length Three With a Condition
Array
Easy
3394. Check if Grid can be Cut into Sections
Array
Sorting
Medium
3396. Minimum Number of Operations to Make Elements in Array Distinct
Array
Hash Table
Easy
3397. Maximum Number of Distinct Elements After Operations
Greedy
Array
Sorting
Medium
3398. Smallest Substring With Identical Characters I
Array
Binary Search
Enumeration
Hard
3399. Smallest Substring With Identical Characters II
String
Binary Search
Hard
3400. Maximum Number of Matching Indices After Right Shifts
Array
Two Pointers
Simulation
Medium
3402. Minimum Operations to Make Columns Strictly Increasing
Greedy
Array
Matrix
Easy
3403. Find the Lexicographically Largest String From the Box I
Two Pointers
String
Enumeration
Medium
3404. Count Special Subsequences
Array
Hash Table
Math
Enumeration
Medium
3405. Count the Number of Arrays with K Matching Adjacent Elements
Math
Combinatorics
Hard
3406. Find the Lexicographically Largest String From the Box II
Two Pointers
String
Hard
3407. Substring Matching Pattern
String
String Matching
Easy
3408. Design Task Manager
Design
Hash Table
Ordered Set
Heap (Priority Queue)
Medium
3411. Maximum Subarray With Equal Products
Array
Math
Enumeration
Number Theory
Sliding Window
Easy
3412. Find Mirror Score of a String
Stack
Hash Table
String
Simulation
Medium
3417. Zigzag Grid Traversal With Skip
Array
Matrix
Simulation
Easy
3418. Maximum Amount of Money Robot Can Earn
Array
Dynamic Programming
Matrix
Medium
3422. Minimum Operations to Make Subarray Elements Equal
Array
Hash Table
Math
Sliding Window
Heap (Priority Queue)
Medium
3423. Maximum Difference Between Adjacent Elements in a Circular Array
Array
Easy
3424. Minimum Cost to Make Arrays Identical
Greedy
Array
Sorting
Medium
3427. Sum of Variable Length Subarrays
Array
Prefix Sum
Easy
3430. Maximum and Minimum Sums of at Most Size K Subarrays
Stack
Array
Math
Monotonic Stack
Hard
3431. Minimum Unlocked Indices to Sort Nums
Array
Hash Table
Medium
3432. Count Partitions with Even Sum Difference
Array
Math
Prefix Sum
Easy
3433. Count Mentions Per User
Array
Math
Sorting
Simulation
Medium
3437. Permutations III
Array
Backtracking
Medium
3438. Find Valid Pair of Adjacent Digits in String
Hash Table
String
Counting
Easy
3439. Reschedule Meetings for Maximum Free Time I
Greedy
Array
Sliding Window
Medium
3440. Reschedule Meetings for Maximum Free Time II
Greedy
Array
Enumeration
Medium
3442. Maximum Difference Between Even and Odd Frequency I
Hash Table
String
Counting
Easy
3443. Maximum Manhattan Distance After K Changes
Hash Table
Math
String
Counting
Medium
3445. Maximum Difference Between Even and Odd Frequency II
String
Enumeration
Prefix Sum
Sliding Window
Hard
3446. Sort Matrix by Diagonals
Array
Matrix
Sorting
Medium
3447. Assign Elements to Groups with Constraints
Array
Hash Table
Medium
3450. Maximum Students on a Single Bench
Array
Hash Table
Easy
3452. Sum of Good Numbers
Array
Easy
3456. Find Special Substring of Length K
String
Easy
3457. Eat Pizzas!
Greedy
Array
Sorting
Medium
3459. Length of Longest V-Shaped Diagonal Segment
Memoization
Array
Dynamic Programming
Matrix
Hard
3460. Longest Common Prefix After at Most One Removal
Two Pointers
String
Medium
3461. Check If Digits Are Equal in String After Operations I
Math
String
Combinatorics
Number Theory
Simulation
Easy
3462. Maximum Sum With at Most K Elements
Greedy
Array
Matrix
Sorting
Heap (Priority Queue)
Medium
3466. Maximum Coin Collection
Array
Dynamic Programming
Medium
3467. Transform Array by Parity
Array
Counting
Sorting
Easy
3471. Find the Largest Almost Missing Integer
Array
Hash Table
Easy
3472. Longest Palindromic Subsequence After at Most K Operations
String
Dynamic Programming
Medium
3476. Maximize Profit from Task Assignment
Greedy
Array
Sorting
Heap (Priority Queue)
Medium
3477. Fruits Into Baskets II
Segment Tree
Array
Binary Search
Ordered Set
Simulation
Easy
3478. Choose K Elements With Maximum Sum
Array
Sorting
Heap (Priority Queue)
Medium
3479. Fruits Into Baskets III
Segment Tree
Array
Binary Search
Ordered Set
Medium
3480. Maximize Subarrays After Removing One Conflicting Pair
Segment Tree
Array
Enumeration
Prefix Sum
Hard
3481. Apply Substitutions
Depth-First Search
Breadth-First Search
Graph
Topological Sort
Array
Hash Table
String
Medium
3483. Unique 3-Digit Even Numbers
Recursion
Array
Hash Table
Enumeration
Easy
3484. Design Spreadsheet
Design
Array
Hash Table
String
Matrix
Medium
3485. Longest Common Prefix of K Strings After Removal
Trie
Array
String
Hard
3487. Maximum Unique Subarray Sum After Deletion
Greedy
Array
Hash Table
Easy
3488. Closest Equal Element Queries
Array
Hash Table
Binary Search
Medium
3491. Phone Number Prefix
Trie
Array
String
Sorting
Easy
3492. Maximum Containers on a Ship
Math
Easy
3493. Properties Graph
Depth-First Search
Breadth-First Search
Union Find
Graph
Array
Hash Table
Medium
3496. Maximize Score After Pair Deletions
Greedy
Array
Medium
3498. Reverse Degree of a String
String
Simulation
Easy
3499. Maximize Active Section with Trade I
String
Enumeration
Medium
3502. Minimum Cost to Reach Every Position
Array
Easy
3503. Longest Palindrome After Substring Concatenation I
Two Pointers
String
Dynamic Programming
Enumeration
Medium
3504. Longest Palindrome After Substring Concatenation II
Two Pointers
String
Dynamic Programming
Hard
3506. Find Time Required to Eliminate Bacterial Strains
Greedy
Array
Math
Heap (Priority Queue)
Hard
3511. Make a Positive Array
Greedy
Array
Prefix Sum
Medium
3512. Minimum Operations to Make Array Sum Divisible by K
Array
Math
Easy
3516. Find Closest Person
Math
Easy
3522. Calculate Score After Performing Instructions
Array
Hash Table
String
Simulation
Medium
3523. Make Array Non-decreasing
Stack
Greedy
Array
Monotonic Stack
Medium
3527. Find the Most Common Response
Array
Hash Table
String
Counting
Medium
3528. Unit Conversion I
Depth-First Search
Breadth-First Search
Graph
Medium
3531. Count Covered Buildings
Array
Hash Table
Sorting
Medium
3532. Path Existence Queries in a Graph I
Union Find
Graph
Array
Hash Table
Binary Search
Medium
3536. Maximum Product of Two Digits
Math
Sorting
Easy
3541. Find Most Frequent Vowel and Consonant
Hash Table
String
Counting
Easy
3545. Minimum Deletions for At Most K Distinct Characters
Greedy
Hash Table
String
Counting
Sorting
Easy
3546. Equal Sum Grid Partition I
Array
Enumeration
Matrix
Prefix Sum
Medium
3549. Multiply Two Polynomials
Array
Math
Hard
3550. Smallest Index With Digit Sum Equal to Index
Array
Math
Easy
3551. Minimum Swaps to Sort by Digit Sum
Array
Hash Table
Sorting
Medium
3552. Grid Teleportation Traversal
Breadth-First Search
Array
Hash Table
Matrix
Medium
3555. Smallest Subarray to Sort in Every Sliding Window
Stack
Greedy
Array
Two Pointers
Sorting
Monotonic Stack
Medium
3556. Sum of Largest Prime Substrings
Hash Table
Math
String
Number Theory
Sorting
Medium
3560. Find Minimum Log Transportation Cost
Math
Easy
3561. Resulting String After Adjacent Removals
Stack
String
Simulation
Medium
3565. Sequential Grid Path Cover
Recursion
Array
Matrix
Medium
3566. Partition Array into Two Equal Product Subsets
Bit Manipulation
Recursion
Array
Enumeration
Medium
3567. Minimum Absolute Difference in Sliding Submatrix
Array
Matrix
Sorting
Medium
3568. Minimum Moves to Clean the Classroom
Bit Manipulation
Breadth-First Search
Array
Hash Table
Matrix
Medium
3571. Find the Shortest Superstring II
String
Easy
3572. Maximize Y‑Sum by Picking a Triplet of Distinct X‑Values
Greedy
Array
Hash Table
Sorting
Heap (Priority Queue)
Medium
3573. Best Time to Buy and Sell Stock V
Array
Dynamic Programming
Medium
3574. Maximize Subarray GCD Score
Array
Math
Enumeration
Number Theory
Hard
3576. Transform Array to All Equal Elements
Greedy
Array
Medium
3577. Count the Number of Computer Unlocking Permutations
Brainteaser
Array
Math
Combinatorics
Medium
3578. Count Partitions With Max-Min Difference at Most K
Queue
Array
Dynamic Programming
Prefix Sum
Sliding Window
Monotonic Queue
Medium
3579. Minimum Steps to Convert String with Operations
Greedy
String
Dynamic Programming
Hard
3581. Count Odd Letters from Number
Hash Table
String
Counting
Simulation
Easy
3582. Generate Tag for Video Caption
String
Simulation
Easy
3583. Count Special Triplets
Array
Hash Table
Counting
Medium
3584. Maximum Product of First and Last Elements of a Subsequence
Array
Two Pointers
Medium
3587. Minimum Adjacent Swaps to Alternate Parity
Greedy
Array
Medium
3590. Kth Smallest Path XOR Sum
Tree
Depth-First Search
Array
Ordered Set
Hard
3591. Check if Any Element Has Prime Frequency
Array
Hash Table
Math
Counting
Number Theory
Easy
3596. Minimum Cost Path with Alternating Directions I
Brainteaser
Math
Medium
3597. Partition String
Trie
Hash Table
String
Simulation
Medium
3598. Longest Common Prefix Between Adjacent Strings After Removals
Array
String
Medium
3599. Partition Array to Minimize XOR
Bit Manipulation
Array
Dynamic Programming
Prefix Sum
Medium
3602. Hexadecimal and Hexatrigesimal Conversion
Math
String
Easy
3606. Coupon Code Validator
Array
Hash Table
String
Sorting
Easy
3610. Minimum Number of Primes to Sum to Target
Array
Math
Dynamic Programming
Number Theory
Medium
3612. Process String with Special Operations I
String
Simulation
Medium
3613. Minimize Maximum Component Cost
Union Find
Graph
Binary Search
Sorting
Medium
3616. Number of Student Replacements
Array
Simulation
Medium
3618. Split Array by Prime Indices
Array
Math
Number Theory
Medium
3619. Count Islands With Total Value Divisible by K
Depth-First Search
Breadth-First Search
Union Find
Array
Matrix
Medium
3622. Check Divisibility by Digit Sum and Product
Math
Easy
3627. Maximum Median Sum of Subsequences of Size 3
Medium
3628. Maximum Number of Subsequences After One Inserting
Greedy
String
Dynamic Programming
Prefix Sum
Medium
3631. Sort Threats by Severity and Exploitability
Array
Sorting
Medium
3633. Earliest Finish Time for Land and Water Rides I
Greedy
Array
Two Pointers
Binary Search
Sorting
Easy
3634. Minimum Removals to Balance Array
Array
Sorting
Sliding Window
Medium
3635. Earliest Finish Time for Land and Water Rides II
Greedy
Array
Two Pointers
Binary Search
Sorting
Medium
3637. Trionic Array I
Array
Easy
3638. Maximum Balanced Shipments
Stack
Greedy
Array
Dynamic Programming
Monotonic Stack
Medium
3641. Longest Semi-Repeating Subarray
Medium
3643. Flip Square Submatrix Vertically
Array
Two Pointers
Matrix
Easy
3644. Maximum K to Sort a Permutation
Bit Manipulation
Array
Medium
3645. Maximum Total from Optimal Activation Order
Greedy
Array
Two Pointers
Sorting
Heap (Priority Queue)
Medium
3647. Maximum Weight in Two Bags
Array
Dynamic Programming
Medium
3658. GCD of Odd and Even Sums
Math
Number Theory
Easy
3659. Partition Array Into K-Distinct Groups
Array
Hash Table
Counting
Medium
3660. Jump Game IX
Array
Dynamic Programming
Medium
3661. Maximum Walls Destroyed by Robots
Array
Binary Search
Dynamic Programming
Sorting
Hard
3662. Filter Characters by Frequency
Hash Table
String
Counting
Easy
3663. Find The Least Frequent Digit
Array
Hash Table
Math
Counting
Easy
3667. Sort Array By Absolute Value
Array
Math
Two Pointers
Sorting
Easy
3668. Restore Finishing Order
Array
Hash Table
Easy
3669. Balanced K-Factor Decomposition
Math
Backtracking
Number Theory
Medium