nlog(n)

class Solution {
public:
    vector<int> getLeastNumbers_Solution(vector<int> input, int k) {
        sort(input.begin(), input.end());
        vector<int> res;
        for(int i = 0; i < k; i ++ )    res.push_back(input[i]);
        return res;
    }
};

nlog(k)

class Solution {
public:
    vector<int> getLeastNumbers_Solution(vector<int> input, int k) {
        priority_queue<int> heap;
        for(int i = 0; i < input.size(); i ++ ){
            heap.push(input[i]);
            if(heap.size() > k) heap.pop();
        }
        vector<int> res;
        while(!heap.empty()){
            res.push_back(heap.top());
            heap.pop();
        }
        reverse(res.begin(), res.end());
        return res;
    }
};