Question 9 Valid Palindrome II

// Some code
```java
/*
Clarification & Assumption
    - string: all characters
    - output: valid defined validPalindrome, could delete one characters

High Level
    - two pointers from left& right
        - two pointers: find their characters if they are same
Middle Level
    - two pointers from left & right
        - if they are same? left++, right--
        - if they are not same? two possible options
            - either check left++ with right
            - or check right-- with left;
TC & SC: O(n), O(1)
*/


class Solution {
    public boolean validPalindrome(String s) {
        // sanity check

        // 
        int left = 0;
        int right = s.length() - 1;
        while (left < right) {
            if (s.charAt(left) == s.charAt(right)) {
                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;
    }
}
```