LintCode : 最长公共子序列

LintCode : 最长公共子序列

给出两个字符串，找到最长公共子序列(LCS)，返回LCS的长度。

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动态规划。大神July讲的很详细，请大家移步这里。

class Solution {
public:
    /**
     * @param A, B: Two strings.
     * @return: The length of longest common subsequence of A and B.
     */
    int longestCommonSubsequence(string A, string B) {
        // write your code here
        int m = A.size();
        int n = B.size();
        vector<vector<int> > dp(m+1, vector<int>(n+1));

        for(int i=0; i<=m; i++){
            for(int j=0; j<=n; j++){
                if(i==0 || j==0){
                    dp[i][j] = 0;
                }
                else{
                    if (A[i-1] == B[j-1]){
                        dp[i][j] =  dp[i-1][j-1] + 1;
                    }
                    else{
                        dp[i][j] = max(max(dp[i-1][j], dp[i][j-1]), dp[i-1][j-1]);
                    }
                }
            }
        }
        return dp[m][n];
    }
};

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string A = “bedaacbade”;
string B = “dccaeedbeb”;

dp数组如下：