1 class Solution { 2 public: 3     string longestPalindrome(string s) { 4         int n = s.length(); 5         int longestS = 0; 6         int maxlen = 1; 7         bool table[1000][1000] = {false}; 8         int i,j,len; 9         for(i = 0 ; i < n ; ++i)10         {11             table[i][i] = true;12         }13         14         for(i = 0 ; i < n-1; ++i)15         {16             if(s[i] == s[i+1])17             {18                 table[i][i+1] = true;19                 longestS = i;20                 maxlen = 2;21             }22         }23         for(len = 3 ; len <= n ; ++len)24         {25             for(i = 0 ; i < n-len+1 ; ++i)26             {27                 j = i+len-1;28                 if(s[i]==s[j] && table[i+1][j-1])29                 {30                     table[i][j] = true;31                     longestS = i;32                     maxlen = len;33                 }34             }35         }36         return s.substr(longestS,maxlen);37     }38 };