需要自己采用快速排序实现以下

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