输入n个整数，找出其中最小的K个数。例如输入4,5,1,6,2,7,3,8这8个数字，则最小的4个数字是1,2,3,4,。

#include "stdafx.h"
#include "stdafx.h"
#include<iostream>
#include<vector>
#include<algorithm>
#include<numeric>
#include<list>
#include<iterator>
#include<queue>
#include<stack>
#include<algorithm>
#include<forward_list>
using namespace std;

class Solution {
public:
vector<int> GetLeastNumbers_Solution(vector<int> input, int k) {
sort(input.begin(),input.end());
vector<int> vec;
if (k > input.size()) return vec;
auto it = input.begin();

for (int i = 0; i < k;i++)
{
if (it == input.end()) break;
vec.push_back(*it);
++it;
}
return vec;
}
};

int main()
{

Solution so;
vector<int> input = { 4,5,1,6,2,7,3,8 };
vector<int> result = so.GetLeastNumbers_Solution(input,4);
for (auto it = result.begin(); it != result.end(); ++it)
cout << *it << "  ";

cout << endl;
return 0;
}

注意：此处主要考察的是排序，我直接调用系统的sort方法进行排序。
要多看堆排序、快排、冒泡等排序算法及其复杂度