Majority Element II

Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times. The algorithm should run in linear time and in O(1) space.

Analyse: map. 

Runtime: 40ms.

class Solution {
public:
    vector<int> majorityElement(vector<int>& nums) {
        int n = nums.size();
        map<int, int> m;
        vector<int> result;
        
        for(int i = 0; i < n; i++){
            if(m.find(nums[i]) != m.end())
                m[nums[i]]++;
            else
                m[nums[i]] = 1;
        }
        
        for(map<int, int>::iterator ite = m.begin();  ite != m.end(); ite++){
            if(ite->second > n / 3)
                result.push_back(ite->first);
        }
        return result;
    }
};