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Longest Common Subsequence

时间:2017-05-15 23:52:55      阅读:381      评论:0      收藏:0      [点我收藏+]

标签:point   har   sequence   http   interview   mon   opera   pre   string   

Problem statement:

Given two strings, find the longest common subsequence (LCS).

Your code should return the length of LCS.

Clarification
Example

For "ABCD" and "EDCA", the LCS is "A" (or "D""C"), return 1.

For "ABCD" and "EACB", the LCS is "AC", return 2.

Solution:

This is a DP problem for two sequences. Such as 72. Edit Distance and 583. Delete Operation for Two Strings.

The key points is also dp[i][j] means the LCS of first i chars in A and first j char in B, and return dp[m][n]

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

 

 

Longest Common Subsequence

标签:point   har   sequence   http   interview   mon   opera   pre   string   

原文地址:http://www.cnblogs.com/wdw828/p/6858799.html

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