import java.util.*;
public class Solution {
/**
*
* @param arr int整型一维数组 the array
* @return int整型
*/
public int maxLength (int[] arr) {
// write code here
Map<Integer,Integer> map = new HashMap<>();
int max = 0;
for (int i = 0, j = 0; i < arr.length; i++){
if (map.containsKey(arr[i])){
j = Math.max(j, map.get(arr[i]) + 1);
}
map.put(arr[i], i);
max = Math.max(max, i - j + 1);
}
return max;
}
}