Overview

• Patterns
• Roadmap
• Interview Process
• How to Study
• The Mindset
• Math Basics
• Runtime to Algo Cheat Sheet
• Keyword to Algo Cheat Sheet
• What to Do When You're Stuck on a Coding Problem

Quick DSA Review

• Basic Data Structures and Algorithms
• Stack Intro
• Queue Intro
• Hashmap Intro
• Data Structures by Language

Basic Algorithms

• Intro to Sorting
• Advanced Sorting Algorithms - Merge Sort | Quick Sort
• Sorting Summary
• Built-in Sort with Custom Comparator

Simulation

• Simulation Coding Problems: Introduction and Strategies

Basics

• Binary Search Intro
• First True

Sorted Array

• Monotonic Function
• First Element Not Smaller Than Target
• First Occurrence
• Square Root Estimation

Implicitly Sorted Array

• Minimum in Rotated Sorted Array
• Peak of Mountain Array

Advanced

• Newspapers

Speedrun

• Binary Search

Intro

• Two Pointers Introduction

Core Concepts

• Understanding Invariants
• Common Invariant Shapes

Same Direction

• Same Direction Family Map
• Remove Duplicates
• Middle of a Linked List
• Move Zeros
• Remove N-th Node from End of Linked List

Opposite Direction

• Opposite Direction Family Map
• Two Sum Sorted
• Valid Palindrome
• Container With Most Water

Sliding Window

• Sliding Window Family Map
• Subarray Sum - Fixed
• Find All Anagrams in a String
• Sliding Window - Longest
• Longest Substring without Repeating Characters
• Sliding Window - Shortest
• Least Consecutive Cards to Match

Prefix Sum

• Introduction
• Subarray Sum Equals Target
• Range Sum Query - Immutable
• Product of Array Except Self

Cycle Finding

• Fast and Slow Family Map
• Linked List Cycle

Decision Making

• Two Pointers Decision Rule

Advanced

• Minimum Window Substring
• Teleporter Arrays
• Two Pointers Synthesis

Speedrun

• Two Pointers
• Monster Breakdown | Two Pointers

Introduction

• Recursion Intro
• Trees
• DFS Intro

DFS on Tree

• Intro
• Max Depth of A Tree
• Visible Tree Node
• Balanced Binary Tree
• Subtree of Another Tree
• Invert Binary Tree

Binary Search Tree

• Binary Search Tree Intro
• Valid Binary Search Tree
• Insert Into BST
• Lowest Common Ancestor of a Binary Search Tree

Advanced

• Reconstruct Binary Tree from Preorder and Inorder Traversal
• Serializing and Deserializing Binary Tree
• Lowest Common Ancestor

Combinatorial Search

• DFS with States
• Backtracking 1
• Generate All Phone Number Combinations

Pruning

• Backtracking 1 - Pruning
• Partition a String Into Palindromes

Additional States

• Backtracking 1 - Additional States
• Generate All Valid Parentheses
• General All Permutations

Aggregation and Memoization

• Backtracking 2 - Aggregation
• Memoization
• Word Break
• Num Ways to Decode a Message
• Min Coins to Make Change

Dedup

• Deduplication
• Combination Sum

Additional Practices

• Subsets

Speedrun

• Backtracking

Introduction

• BFS Intro

BFS on Tree

• Binary Tree Level Order Traversal
• Binary Tree ZigZag Level Order Traversal
• Binary Tree Right Side View
• Binary Tree Min Depth

Speedrun

• Trees

Introduction

• Graph Intro
• BFS on Graphs
• DFS on Graph
• BFS vs DFS

Vanilla BFS

• Shortest Path
• Clone Graph

Matrix as Graph

• Matrix as Graph
• Flood Fill
• Number of Islands
• Knight Minimum Moves
• Walls and Gates / Zombie in Matrix
• Pacific Atlantic Water Flow

Implicit Graph

• Word Ladder
• Open the Lock
• Sliding Puzzle

Directed Graph / Topological Sort

• Topological Sort Intro
• Task Scheduling
• Reconstructing Sequence
• Task Scheduling 2
• Alien Dictionary
• Course Schedule

Weighted Graph

• Dijkstra's Algorithm | Shortest Path in a Weighted Graph

Minimum Spanning Tree

• Introduction to Minimum Spanning Tree
• Minimum Spanning Tree | Forests

Speedrun

• Graph Part 1
• Graph Part 2

Introduction

• Heap Intro

Top K

• K Closest points
• Merge K Sorted Lists
• Kth Largest Element in an Array
• Kth Smallest Element in a Sorted Matrix

Moving Best

• Reorganize String
• Ugly Number

Multiple Heaps

• Median of Data Stream

Speedrun

• Heap

Introduction

• Dynamic Programming Intro

Warmup

• Climbing Stairs
• N-th Tribonacci Number

Constant Transition

• Constant Transition DP Introduction
• House Robber
• Min Cost Climbing Stairs
• Minimum Cost For Tickets

Grid

• Grid DP Introduction
• Unique Paths
• Unique Paths with Obstacles
• Minimum Path Sum
• Maximal Square
• Triangle
• Dungeon Game

Dual-Sequence

• Dual-Sequence DP Introduction
• Longest Common Subsequence
• Edit Distance
• Delete String
• Distinct Subsequences
• Shortest Common Supersequence

Non-constant Transition

• Non-constant Transition DP Introduction
• Longest Increasing Subsequence
• Partition Array for Maximum Sum
• Largest Divisible Subset
• Divisor Game

Knapsack, Weight-Only

• Knapsack DP Introduction
• Weight-Only knapsack
• Partition Equal Subset Sum
• Target Sum
• Unbounded Knapsack Introduction
• Coin Change II
• Coin Change, Optimization
• Perfect Squares

Knapsack, Weight+Value

• 0/1 Knapsack Introduction
• 0/1 Knapsack Practice Problem
• Bounded Knapsack Introduction
• Bounded Knapsack

Interval

• Interval DP Intro
• Palindromic Substrings
• Coin Game
• Longest Palindromic Subsequence

Topological Sort

• Topological Sort DP Introduction
• Longest Increasing Path in a Matrix
• Longest String Chain

Trees

• Tree DP Introduction
• House Robber III

Bitmask

• Bitmask Introduction
• Bitmask DP
• Minimum Cost to Visit Every Node

Additional Practices

• DP Practice List

Speedrun

• DP Part 1
• DP Part 2

Disjoint Set Union | Union Find

• DSU/Union Find Fundamentals
• DSU Optimizations: Path Compression and Union by Rank
• DSU Introductory Problem
• Size of Connected Components
• Merge User Accounts
• Number of Connected Components
• Umbristan | Reverse Union Find

Trie

• Trie Introduction
• Autocomplete
• Prefix Count
• Add and Search Words Data Structure
• Word Search II

Data Structure Design

• LRU Cache

Segment Tree

• Segment Tree Intro
• Range max

Speedrun

• Trie & Union-Find

Interval

• Intervals
• Merge Intervals
• Insert Interval
• Meeting Rooms
• Meeting Rooms II
• Non-overlapping Intervals
• Minimum Number of Arrows to Burst Balloons
• Partition Labels

Stack

• Min Stack
• Basic Calculator

Monotonic Stack

• Monotonic Stack Intro
• Sliding Window Maximum
• Daily Temperatures
• Next Greater Element II
• Largest Rectangle in Histogram

Divide and Conquer

• Divide and Conquer Intro
• The Skyline Problem
• Count of Smaller Numbers After Self

Line Sweep

• Line-Sweep Introduction
• Union Area of Rectangles

Tree Traversal without Recursion

• Closest BST Values II

Greedy

• Greedy Introduction
• Gas Station

Math

• Prime Sieve Intro
• N-th prime

Matrix

• Sparse Matrix Multiplication

Speedrun

• Stack & Intervals
• Mixed Review

Amazon OA

• Amazon OA
• Robot in Circle
• Number Game
• Find All Combination of Numbers that Sum to a Target
• Fill The Truck
• Slowest Key
• Five Star Sellers
• Number of Ways to Split Into Primes
• Storage Optimization
• Music Pair
• Minimum Difficulty of a Job Schedule
• Autoscale Policy, Utilization Check
• Optimal Utilization
• Merge Two Sorted Lists
• Two Sum
• Shopping Patterns
• Reorder Data in Log Files
• Top K Keywords

Microsoft OA

• Microsoft OA
• Max Network Rank
• Minimum Adj Swaps
• Lexicographically Smallest String
• Longest Substring
• Min Moves to Obtain String Without 3 Identical Consecutive Letters
• String
• Min Steps to Make Piles Equal Height
• Day of week
• Max Inserts to Obtain String Without 3 Consecutive 'a'
• Concatenated String Length
• Largest K such that both K and -K exist in array
• Maximum Length of a Concatenated String
• Sum to Zero
• Min Deletions
• Particle Velocity
• Jump Game
• Fair Indexes
• Partition array into N subsets with balanced sum

Google OA

• Google OA
• Compare Strings
• Largest Subarray
• Maximum Area Serving Cake
• Minimum Number of Decreasing Subsequence Partitions
• Pick Up Coupons
• Rose Garden
• Smallest Integer Satisfying the Rule
• Fill 2D Array
• Water Plants
• Split Strings
• Google Online Assessment 2021 (OA) - Rings on Rods

Twitter OA

• Twitter OA
• K-Different Pairs
• Weird Faculty
• Social Network
• University Career Fair
• Game Events
• Activate Fountain
• Final Discounted Price
• Partition Array
• Authentication Tokens
• Parking Dilemma
• Efficient Job Processing Service
• Unique Twitter User ID Set