插入排序

class Solution {
public:
    vector<int> GetLeastNumbers_Solution(vector<int> input, int k) {
        vector<int> ret;
        if(input.size()<=0 || k>input.size()) return ret;
        for(int i = 1; i<input.size();i++)
        {
            for(int j = i-1;j>=0&&input[j+1]<=input[j];j--)
            {
                swap(input[j+1], input[j]);
            }
        }
        for(int i = 0; i<k;i++)
        {
            ret.push_back(input[i]);
        }
        return ret;
    }
    void swap(int &a, int &b)
    {
        int temp = a;
        a = b;
        b = temp;
    }
};