Minimum Swaps to Group All 1's Together
Given a string s
, return true
if the s
can be palindrome after deleting at most one character from it.
Example 1:
Input: s = "aba"
Output: true
Example 2:
Input: s = "abca"
Output: true
Explanation: You could delete the character 'c'.
Example 3:
Input: s = "abc"
Output: false
Constraints:
1 <= s.length <= 105
s
consists of lowercase English letters.
Solution
The best approach to solve this problem is using two pointers in opposite directions.
Similar to Valid Palindrome, we will initialize two pointers on the two ends of the string and work our way inside.
We will perform the same palindrome validation by matching the characters at the l
and r
pointers.
If their corresponding characters are different, then we know we must delete one character at one of the l
or r
position.
Then, we can check whether the unprocessed substring (excluding the deleted character) is a palindrome.
In Valid Palindrome, we had implemented is_palindrome
with two pointers, here, we are using an iterative approach for two pointers.
The left pointer is i
and the right pointer is slen - i
, where slen
is len(s) - 1
.
Implementation
1def validPalindrome(self, s: str) -> bool:
2 def isPalindrome(s: str):
3 slen = len(s)-1
4 for i in range(slen//2 + 1):
5 if s[i] != s[slen-i]: return False
6 return True
7
8 l, r = 0, len(s)-1
9 while l < r:
10 if s[l] != s[r]:
11 return isPalindrome(s[l+1:r+1]) or isPalindrome(s[l:r])
12 l += 1
13 r -= 1
14 return True
Ready to land your dream job?
Unlock your dream job with a 2-minute evaluator for a personalized learning plan!
Start EvaluatorConsider the classic dynamic programming of fibonacci numbers, what is the recurrence relation?
Recommended Readings
LeetCode Patterns Your Personal Dijkstra's Algorithm to Landing Your Dream Job The goal of AlgoMonster is to help you get a job in the shortest amount of time possible in a data driven way We compiled datasets of tech interview problems and broke them down by patterns This way we
Recursion Recursion is one of the most important concepts in computer science Simply speaking recursion is the process of a function calling itself Using a real life analogy imagine a scenario where you invite your friends to lunch https algomonster s3 us east 2 amazonaws com recursion jpg You first
Runtime Overview When learning about algorithms and data structures you'll frequently encounter the term time complexity This concept is fundamental in computer science and offers insights into how long an algorithm takes to complete given a certain input size What is Time Complexity Time complexity represents the amount of time
Got a question? Ask the Monster Assistant anything you don't understand.
Still not clear?  Submit the part you don't understand to our editors. Or join our Discord and ask the community.