Longest Palindromic Substring

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

1. import java.io.IOException;
2. public class LongestSubstringPalindrome
3. {
4.   public static void main(String[] args) throws IOException
5.   {
6.     // String word = "abbcbba";
7.     String str = "abbagoodteacher";
8.     System.out.println(longestPalindrome(str));
9.   }
10.   public static String longestPalindrome(String s)
11.   {
12.     int length = s.length();
13.     if (s == null || length < 2)
14.     {
15.       return s;
16.     }
17.     boolean isPalindrome[][] = new boolean[length][length];
18.     int left = 0;
19.     int right = 0;
20.     for (int j = 1; j < length; j++)
21.     {
22.       for (int i = 0; i < j; i++)
23.       {
24.         boolean isInnerWordPalindrome = isPalindrome[i + 1][j - 1] || j - i <= 2;
25.         if (s.charAt(i) == s.charAt(j) && isInnerWordPalindrome)
26.         {
27.           isPalindrome[i][j] = true;
28.           if (j - i > right - left)
29.           {
30.             left = i;
31.             right = j;
32.           }
33.         }
34.       }
35.     }
36.     return s.substring(left, right + 1);
37.   }
38. }

Output: abba