leetcode Longest Palindromic Substring

优秀的解法：http://www.cnblogs.com/xubenben/p/3330746.html

代码：（Time Limit  Exceeded），这博客已经被我写成我的刷题实况了。接下来还有新的写法。

 1 #include<iostream>

 2 #include<string>

 3 

 4 using namespace std;

 5 

 6 string longestPalindrome(string s)

 7 {

 8     int n = s.length();

 9     int max = n;

10     if (n == 1)

11         return s;

12     while (max != 1)

13     {

14         int i = n - max;

15         int j = 0;

16         while (j <= i)

17         {

18             int t = j;

19             int middle = max / 2 + j - 1;

20             for (; t <= middle; t++)

21             {

22                 if (max % 2 == 1)

23                 {

24                     if (s[t] != s[middle * 2 + 2 - t])

25                     {

26                         break;

27                     }

28                 }

29                 else

30                 {

31                     if (s[t] != s[middle * 2 - t + 1])

32                     {

33                         break;

34                     }

35                 }

36             }

37             if (t == middle + 1)

38             {

39                 return s.substr(j, j+max);

40             }

41             else

42             {

43                 j++;

44             }

45         }

46         max--;

47     }

48 }

49 

50 int main()

51 {

52     string s = "a";

53     cout << s << endl;

54     cout << longestPalindrome(s) << endl;

55 }