最长回文子串[中心扩展思想]

#include <iostream>#include<string>using namespace std;    string findLongestPalindrome(string &s)      {          int length=s.size();          int maxlength=0;          int start,j,k;                for(int i=0;i<length;i++)          { if(length%2!=0){//奇偶判断j=i-1;k=i+1;}else{j=i;k=i+1;}            while(j>=0&&k<length&&s.at(j)==s.at(k))              {                  if(k-j+1>maxlength)                  {                      maxlength=k-j+1;                      start=j;                  }                  j--;                  k++;              }          }          if(maxlength>0)              return s.substr(start,maxlength);          return NULL;      }void main(){string s;getline(cin,s);cout<<findLongestPalindrome(s)<<endl;}

更多信息：

http://blog.csdn.net/kangroger/article/details/37742639