leetcode讲解–961. N-Repeated Element in Size 2N Array

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题目
In a array A of size 2N, there are N+1 unique elements, and exactly one of these elements is repeated N times.
Return the element repeated N times.
Example 1:
Input: [1,2,3,3]
Output: 3
Example 2:
Input: [2,1,2,5,3,2]
Output: 2
Example 3:
Input: [5,1,5,2,5,3,5,4]
Output: 5
Note:

4 <= A.length <= 10000
0 <= A[i] < 10000

A.length is even

题目地址
讲解
这个题目很简单，只要扫描一遍数组，遇到一个数出现两次，就找到了这个数。
Java 代码
class Solution {
public int repeatedNTimes(int[] A) {
Map<Integer, Integer> map = new HashMap<>();
for(int x:A){
Integer count = map.get(x);
if(count==null){
map.put(x, 1);
}else{
return x;
}
}
return 0;
}
}