have.java

public class Solution {
 public String longestPalindrome(String s) {
 if (s.length() <= 1) {
 return s;
 }

 int maxLen = 1;
 String maxStr = s.substring(0, 1);

 for (int i = 0; i < s.length(); i++) {
 for (int j = i + maxLen; j <= s.length(); j++) {
 if (j - i > maxLen && isPalindrome(s.substring(i, j))) {
 maxLen = j - i;
 maxStr = s.substring(i, j);
 }
 }
 }

 return maxStr;
 }

 private boolean isPalindrome(String str) {
 int left = 0;
 int right = str.length() - 1;

 while (left < right) {
 if (str.charAt(left) != str.charAt(right)) {
 return false;
 }
 left++;
 right--;
 }

 return true;
 }
}