leetcode: Majority Element

Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.

You may assume that the array is non-empty and the majority element always exist in the array.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.  

#include <iostream>
#include <vector>
#include <unordered_map>

using namespace std;

class Solution {
public:
    int majorityElement(vector<int> &num) {
	unordered_map<int,int> *map=new unordered_map<int,int>();
	int max=1;
	vector<int>::iterator iter=num.begin();
	map->insert(make_pair(*iter,1));
	int result=*iter;
	++iter;
	vector<int>::iterator end = num.end();
        for(;iter!=end;++iter){
		unordered_map<int,int>::iterator tmp=map->find(*iter);
		if(tmp!=map->end()){
			if(tmp->second+1>max){
				result=*iter;
				max=tmp->second+1;
			}
			map->erase(*iter);
			map->insert(make_pair(*iter,tmp->second+1));
		}else{
			map->insert(make_pair(*iter,1));
		}
	}
	return result;
    }
};
int main() {
    Solution s;
    int n[] = { 1,1,3,3,3,24,85,23,2};
    vector<int> a(&n[0], &n[5]);
    cout<<s.majorityElement(a)<<endl;
    return 0;
}