116th LeetCode Weekly Contest N-Repeated Element in Size 2N Array

Posted 2021-01-29 樱花落舞

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:

1. 4 <= A.length <= 10000
2. 0 <= A[i] < 10000
3. A.length is even

这种，没啥好说的吧

class Solution {
public:
    int repeatedNTimes(vector<int>& A) {
        int len = A.size();
        int num = len/2;
        map<int,int>Mp;
        for(int i=0;i<len;i++){
            Mp[A[i]]++;
        }
        for(auto it : Mp){
            int x = it.second;
            //cout<<x<<endl;
            if(x == num){
                return it.first;
            }
        }
    }
};