Longest Palindromic Substring (DP)

Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.

public class Solution {


    public String longestPalindrome(String s) {


int n = s.length();
char[] charArray = s.toCharArray();


int longestBegin = 0;
int maxLen = 1;


boolean[][] table = new boolean[1000][1000];
for (int i = 0; i < 1000; i++) {
for (int j = 0; j < 1000; j++) {
table[i][j] = false;
}
}


for (int i = 0; i < n; i++) {
table[i][i] = true;
}


for (int i = 0; i < n - 1; i++) {
if (charArray[i] == charArray[i + 1]) {
table[i][i + 1] = true;
longestBegin = i;
maxLen = 2;
}
}


for (int len = 3; len <= n; len++) {
for (int i = 0; i <= n-1; i++) {
int j = i + len - 1;
if ( j<=n-1 && charArray[i] == charArray[j] && table[i + 1][j - 1]) {
table[i][j] = true;


if (maxLen < len) {
longestBegin = i;
maxLen = len;
}


}
}
}


return s.substring(longestBegin, longestBegin + maxLen);


}
}