LC 516. Longest Palindromic Subsequence
阿新 • • 發佈:2019-02-11
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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".
Runtime: 128 ms, faster than 59.09% of C++ online submissions for Longest Palindromic Subsequence. Memory Usage: 90.5 MB, less than 0.79% of C++ online submissions for Longest Palindromic Subsequence.
class Solution { public: int longestPalindromeSubseq(string s) { int N = s.size(); vector<vector<int>> dp(N, vector<int>(N,0)); for(int i=0; i<N; i++) { dp[i][i] = 1; } for(int gap=1; gap<s.size(); gap++) { for(int i=0; i<N; i++) { int j = i+gap; if(i+gap >= N) continue; if(s[i] == s[j]) { 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]; } };
LC 516. Longest Palindromic Subsequence