LeetCode1035. Uncrossed Lines

1035. Uncrossed Lines

We write the integers of A and B (in the order they are given) on two separate horizontal lines.

Now, we may draw a straight line connecting two numbers A[i] and B[j] as long as A[i] == B[j], and the line we draw does not intersect any other connecting (non-horizontal) line.

Return the maximum number of connecting lines we can draw in this way.

Example 1:

Input: A = [1,4,2], B = [1,2,4]
Output: 2
Explanation: We can draw 2 uncrossed lines as in the diagram.
We cannot draw 3 uncrossed lines, because the line from A[1]=4 to B[2]=4 
will intersect the line from A[2]=2 to B[1]=2.

Example 2:

Input: A = [2,5,1,2,5], B = [10,5,2,1,5,2]
Output: 3

Example 3:

Input: A = [1,3,7,1,7,5], B = [1,9,2,5,1]
Output: 2

---

题目：求解最长公共子串。

思路：参考最长公共子序列。

工程代码下载

class Solution {
public:
    int maxUncrossedLines(vector<int>& A, vector<int>& B) {
        int m = A.size(), 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(A[i] == B[j])
                    dp[i+1][j+1] = dp[i][j] + 1;
                else
                    dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
            }
        }
        
        return dp[m][n];
    }
};