leetcode 5. Longest Palindromic Substring

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.

Example:

Input: "babad"

Output: "bab"

Note: "aba" is also a valid answer.
Example:

Input: "cbbd"

Output: "bb"


class Solution {
public:
    string longestPalindrome(string s) {
        string result_s;
        int test;
        bool dp[s.length()][s.length()];

        int result = 0;
        for(int i = 0; i < s.length();i++) {
            dp[i][i] = 1;
            result = 1;
            result_s = s[0];

        }
        for(int i = s.length() - 1; i >= 0; i--) {
            for(int j = i; j < s.length();j++) {
                dp[i][j] = (s[i] == s[j]) // chars at i and j should match
                           && 
                           ( j-i < 3  // if window is less than or equal to 3, just end chars should match
                             || dp[i+1][j-1]  ); 
                if(dp[i][j] && j - i + 1 > result) {
                    result = j - i + 1;
                    result_s = s.substr(i, result);
                }

            }
        }
        return result_s;

    }
};