[leetcode-718-Maximum Length of Repeated Subarray]

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

思路：

动态规划，dp[i][j]代表长度为i的a与长度为j的b 出现相同的子数组的长度值。

如果a[i-1]==b[j-1]    dp[i][j] = dp[i-1][j-1]+1;

 

int findLength(vector<int>& A, vector<int>& B)
{
    int m = A.size(), n = B.size();
    vector<vector<int>>dp(m + 1, vector<int>(n + 1, 0));
    int ret = 0;

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