718. Maximum Length of Repeated Subarray

#week9

Given two integer arrays A and B, return the maximum length of an subarray that appears in both arrays.

Example 1:

Input:
A: [1,2,3,2,1]
B: [3,2,1,4,7]
Output: 3
Explanation: 
The repeated subarray with maximum length is [3, 2, 1].

Note:

1. 1 <= len(A), len(B) <= 1000
2. 0 <= A[i], B[i] < 100

分析

　　 b　　a　　b

c　　0　　0　　0

a　　0　　1　　0

b　　1　　0　　2

a　　0　　2　　0

dp[i][j] = dp[i-1][j-1] + 1;

题解

class Solution {
public:
    int findLength(vector<int>& a, vector<int>& b) {
        int na = a.size(), nb= b.size();
        int dp[na+1][nb+1] = {};
        int mx = 0;
        for (int i = 1; i <= na; ++i) for (int j = 1; j <=nb; ++j) {
            if (a[i-1] == b[j-1]) dp[i][j] = dp[i-1][j-1] + 1;
            mx = max(mx,dp[i][j]);
        }
        
        return mx;
    }
};