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

Hint:
寻找串A,B的最长相同子串，可以使用动态规划的方法：
对A串的每个数A[i]，扫描B串，如果B[j]等于该数，我们需要知道B[j-1]是否与A[i-1]相等，前面还有多少个相等。
因此我们需要维护一个数组，存储上一次扫描获得的信息。
时间复杂度O（nm）

class Solution {public:    int findLength(vector<int>& A, vector<int>& B) {        int result = 0, lena = A.size(), lenb = B.size();        vector<int> scmp(lenb + 1, 0);        for (int i = 0; i < lena; ++i) {            for (int j = lenb; j > 0; --j) {                scmp[j] = (A[i] == B[j - 1]) ? scmp[j - 1] + 1 : 0;                result = std::max(result, scmp[j]);            }        }        return result;    }};