347. Top K Frequent Elements（LeetCode）

Given a non-empty array of integers, return the k most frequent elements.

For example,
Given [1,1,1,2,2,3] and k = 2, return [1,2].

Note: 

• You may assume k is always valid, 1 ? k ? number of unique elements.
• Your algorithm's time complexity must be better than O(n log n), where n is the array's size.

class Solution {
public:
    vector<int> topKFrequent(vector<int>& nums, int k) {
     map<int, int> m;
        map<int, int>::iterator ite;
        for (int i = 0; i < nums.size(); i++)
        {
            m[nums[i]]++;
        }
        vector<int> vet;
        int max = INT_MIN;
        int max1 = 0;
        while (k)
        {
            int count = 0;
            for (ite = m.begin(); ite != m.end(); ite++)
            {
                if (ite->second > max)
                {
                    max = ite->second;
                    max1 = ite->first;
                    count++;
                }
            }
            m[max1] = INT_MIN;
            if (count != 0)
            {
                vet.push_back(max1);
            }
            max = INT_MIN;
            k--;
        }
        return vet;
    }
};