LeetCode [680] Valid Palindrome II

Given a non-empty string s, you may delete at most one character. Judge whether you can make it a palindrome.

Example 1:

Input: "aba"
Output: True

Example 2:

Input: "abca"
Output: True
Explanation: You could delete the character 'c'.

Note:

1. The string will only contain lowercase characters a-z. The maximum length of the string is 50000.

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class Solution { public: bool validPalindrome(string s) { int l = 0, r = s.size()-1; while(l<r) { if(s[l]!=s[r]) { if(!helper(s, l+1, r) && !helper(s, l, r-1)) return false; else return true; } else { l++; r--; } } return true; } bool helper(string s, int l, int r) { while(l<r) { if(s[l++]!=s[r--]) return false; } return true; } };