原题链接在这里：

题目：

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: 3Explanation: 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

题解：

The subarray must be continuous. 

dp[i][j] denotes the maximum length of repeated subarray between A up to index i and B up to index j.

if(A[i] == B[j]) dp[i][j] = dp[i-1][j-1]+1.

if(A[i] != B[j]) d[i][j] = 0.

Time Complexity: O(m*n).

Space: O(m*n).

AC Java:

1 class Solution { 2     public int findLength(int[] A, int[] B) { 3         if(A == null || A.length == 0 || B == null || B.length == 0){ 4             return 0; 5         } 6          7         int m = A.length; 8         int n = B.length; 9         int [][] dp = new int[m+1][n+1];10         int res = 0;11         for(int i = 1; i<=m; i++){12             for(int j = 1; j<=n; j++){13                 if(A[i-1] == B[j-1]){14                     dp[i][j] = dp[i-1][j-1]+1;15                     res = Math.max(res, dp[i][j]);16                 }17             }18         }19         20         return res;21     }22 }

类似, , .