這道題多想想，心情不好不貼其他代碼了

解法

class Solution {
public:
    vector<int> topKFrequent(vector<int>& nums, int k) {
        vector<int, int> output;
        unordered_map<int, int> list;
        priority_queue<int, int> find;
        for (int i = 0; i < nums.size(); i ++)
            ++ list[nums[i]];
        for (unordered_map<int, int> iterator i = list.begin(); i != list.end(); i ++)
            find.push(make_pair(i -> second, i -> first));
        while (find.size() != k)
            find.pop();
        while (find.size())
            output
    }
};