面试题30 最小的K个数

题目描述

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,。

class Solution {
public:
    multiset<int, greater<int>> a;
    vector<int> v;
    vector<int> GetLeastNumbers_Solution(vector<int> input, int k) {
        a.clear();
        if (k < 1 || input.size() <= 0 || k > input.size()){
            return v;
        }
        
        for (int i = 0; i < input.size(); i++){
            if (a.size() < k)
                a.insert(input[i]);
            else{
                multiset<int, greater<int>>::iterator iter = a.begin();
                if (*iter > input[i]){
                    a.erase(iter);
                    a.insert(input[i]);
                }
            }
        }
        multiset<int, greater<int>>::iterator iter = a.begin();
        while (iter != a.end()){
            v.push_back(*iter);
            iter++;
        }
        return v;
    }
};