【LeetCode】Longest Palindromic Substring

参考：http://blog.youkuaiyun.com/soszou/article/details/37312317

public class Solution {
    public String longestPalindrome(String s) {
        int len = s.length();
        String ans = "";
        String tmp;
        for(int i = 0; i < len ; i++){
           tmp = solve(s, i , i);
           if(tmp.length() > ans.length()){
               ans = tmp;
           }
           if(i + 1 < len){
           tmp = solve(s, i, i + 1);
             if(tmp.length() > ans.length()){
               ans = tmp;
           }
           }
        }
        return ans;
    }
    public String solve(String s, int x, int y){//
        int len = s.length();
        while(x >= 0 && y < len && s.charAt(x) == s.charAt(y)){
            x --;
            y ++;
        }
        return s.substring(x + 1, y);
    }
}