LeetCode OJ：Longest Palindromic Substring（最长的回文字串）

Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.

玩了两天dota2,罪过罪过，还是应该老老实实刷题啊。

题目求得是最长的回文子串，这里使用的是暴力的解法，也就是解决两种回文"asdsa"以及"assa"，即奇数以及偶数回文，相当于用了二重循环，代码如下：

 class Solution {
 public:
     string longestPalindrome(string s) {
         if (!s.size()) return "";
         string ret;
         string tmp;
         for (int i = ; i < s.size(); ++i){
             tmp = findPal(s, i - , i + );
             if (tmp.size() > ret.size())
                 ret = tmp;
             tmp = findPal(s, i , i + );
             if (tmp.size() > ret.size())
                 ret = tmp;
         }
         return ret;
     }

     string findPal(string & s,  int left, int right)
     {
         if (left < )
             return s.substr(left + , );
         if (right >= s.size())
             return s.substr(right - , );

         while (left >=  && right < s.size()){
             if (s[left] != s[right])
                 break;
             left--;
             right++;
         }
         left++;
         return s.substr(left, right - left);
     }
 };