Method longestPalindrome

java/005_Longest_Palindromic_Substring.java:3–17

(String s)

public class Solution {
    // example in leetcode book
    public String longestPalindrome(String s) {
        int start = 0, end = 0;
        for (int i = 0; i < s.length(); i++) {
            // aba
            int len1 = expandAroundCenter(s, i, i);
            // bb
            int len2 = expandAroundCenter(s, i, i + 1);
            int len = Math.max(len1, len2);
            if (len > end - start) {
                start = i - (len - 1) / 2;
                end = i + len / 2;
            }
        }
        return s.substring(start, end + 1);
    }

    private int expandAroundCenter(String s, int left, int right) {
        int L = left, R = right;