Leetcode 算法习题 第十四周

516. Longest Palindromic Subsequence

Given a string s, find the longest palindromic subsequence’s length in s. You may assume that the maximum length of s is 1000.
Example 1:
Input:
“bbbab”
Output:
4
One possible longest palindromic subsequence is “bbbb”.
Example 2:
Input:
“cbbd”
Output:
2
One possible longest palindromic subsequence is “bb”.

题目大意

找到最长回文序列，不要求连续

我的解答

class Solution {public:    int longestPalindromeSubseq(string s) {        int n = s.size();        vector<vector<int>> dp(n+1,vector<int>(n+1,0));        for(int i = n-1; i >= 0; i--){            dp[i][i] = 1;            for(int j = i+1; j < n; j++){                if(s[j] == s[i]){                    dp[i][j] = dp[i+1][j-1] + 2;                }                else{                    dp[i][j] = max(dp[i+1][j],dp[i][j-1]);                }            }        }        return dp[0][n-1];    }};