最小的K个数

　　题目：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。

 1 vector<int> GetLeastNumbers_Solution(vector<int> input, int k) {
 2         vector<int> result;
 3         if(input.size()<=0||input.size()<k)
 4             return vector<int>();
 5         
 6         multiset<int,greater<int>> leastNumber;
 7         vector<int>::iterator inputIter = input.begin();
 8         for(;inputIter!=input.end();inputIter++){
 9             if(leastNumber.size()<k)
10                 leastNumber.insert(*inputIter);
11             else{
12                 multiset<int,greater<int>>::iterator leastIter = leastNumber.begin();
13                 if(*inputIter < *leastIter){
14                     leastNumber.erase(leastIter);
15                     leastNumber.insert(*inputIter);
16                 }
17             }
18         }
19         return vector<int>(leastNumber.begin(),leastNumber.end());
20     }