229. Majority Element II

https://leetcode.com/problems/majority-element-ii/

1. Use hashmap:

//36 ms    15.6 MB
class Solution {
public:
    vector<int> majorityElement(vector<int>& nums) {
        map<int, int> counter;
        vector<int> result;
        for(int i=0; i<nums.size(); i++)
            counter[nums[i]]++;
        for(map<int, int>::iterator it=counter.begin(); it!=counter.end(); it++)
            if(it->second > nums.size()/3)
                result.push_back(it->first);
        return result;
    }
};