leetcode516 Longest Palindromic Subsequence

思路:

区间dp。

实现:

 class Solution
 {
 public:
     int longestPalindromeSubseq(string s)
     {
         int n = s.length();
         int dp[][];
         for (int i = ; i < n; i++)
         {
             dp[i][i] = ;
             if (i != n - ) dp[i][i + ] = (s[i] == s[i + ] ?  : );
         }
         for (int i = n - ; i >= ; i--)
         {
             for (int j = i + ; j < n; j++)
             {
                 if (s[i] == s[j]) dp[i][j] = dp[i + ][j - ] + ;
                 else dp[i][j] = max(dp[i + ][j], dp[i][j - ]);
             }
         }
         return dp[][n - ];
     }
 };