Valid Palindrome II - LeetCode solutions

Problem

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 <= 10^5
s consists of lowercase English letters.

Solution (Java)

class Solution {
    public boolean validPalindrome(String s) {
        int l = 0;
        int r = s.length() - 1;
        while (l < r) {
            if (s.charAt(l) != s.charAt(r)) {
                return isPalindrome(s.substring(l + 1, r + 1)) || isPalindrome(s.substring(l, r));
            }
            l++;
            r--;
        }
        return true;
    }

    private boolean isPalindrome(String s) {
        int l = 0;
        int r = s.length() - 1;
        while (l < r) {
            if (s.charAt(l) != s.charAt(r)) {
                return false;
            }
            l++;
            r--;
        }
        return true;
    }
}

Explain:

nope.

Complexity:

Time complexity : O(n).
Space complexity : O(n).