Longest Palindromic String

/*
Given a string s, return the longest palindromic substring in s.
 

Example 1:

Input: s = "babad"
Output: "bab"
Note: "aba" is also a valid answer.
Example 2:

Input: s = "cbbd"
Output: "bb"
Example 3:

Input: s = "a"
Output: "a"

*/




class Solution {
    public String longestPalindrome(String s) {
        int n = s.length();
        int left=0, right=0;
        if(n<2)
           return s;
        if(n==2 && s.charAt(0)== s.charAt(1))
            return s;
            
        boolean memo[][] = new boolean[n][n];
        
        for(int index=0; index<n; index++){
            for(int i =0, j= index; j<n; i++, j++){
                if(index ==0 ){
                    memo[i][j] = true;            
                }else if(index == 1){
                    memo[i][j] =  s.charAt(i)== s.charAt(j)?true:false;  
                }else{
                    memo[i][j] = (s.charAt(i)== s.charAt(j))&&(memo[i+1][j-1]) ? true: false;
                }
                if(memo[i][j]){
                    left = i;
                    right = j;
                }
            }
        }
        return s.substring(left, right+1).toString();
    }
}