680. Valid Palindrome II

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:

class Solution {
    public boolean validPalindrome(String s) {
        int left = 0;
        int right = s.length() - 1;

        while(left <= right){
            char l = s.charAt(left);
            char r = s.charAt(right);

            if (l == r){
                left++;
                right--;
            }else{
                return isPalindrome(s, left + 1, right) || isPalindrome(s, left, right-1);
            }
        }

        return true;

    }

    private boolean isPalindrome(String s, int left, int right){
        while(left <= right){
            if (s.charAt(left) != s.charAt(right)){
                return false;
            }
            left++;
            right--;
        }
        return true;
    }
}
// TC: O(n)
// SC: O(1)