5. Longest Palindromic Substring

• Question Description
  
• My Key

package LeetCode;
public class Test {
      private static int index;
      private static int len;
      
      public static void main(String[] args)
      {
            System.out.println(longestPalindrome("fjajljfal"));
      }
      
      public static String longestPalindrome(String s) {
          if (s.length() < 2)
            return s;
          for (int i = 0; i < s.length() - 1; i++) {
            PalindromeHelper(s, i, i);
            PalindromeHelper(s, i, i + 1);
          }
          return s.substring(index, index + len);
        }
  public static void PalindromeHelper(String s, int l, int r) {
    while (l >= 0 && r < s.length() && s.charAt(l) == s.charAt(r)) {
      l--;
      r++;
    }
    if (len < r - l - 1) {
      index = l + 1;
      len = r - l - 1;
    }
  }
}