采用优先队列来求解问题

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