題目描述

輸入n個整數，找出其中最小的K個數。例如輸入4,5,1,6,2,7,3,8這8個數字，則最小的4個數字是1,2,3,4,。

C++

//堆排
class Solution {
public:
    vector<int> GetLeastNumbers_Solution(vector<int> input, int k) {
        vector<int> res;
        if(input.empty()||k>(int)input.size()||k<1)
            return res;
        make_heap(input.begin(),input.end(),greater<int>());//生成小根堆
        for(int i=0;i<k;i++)
            {
             res.push_back(input.front());
             pop_heap(input.begin(),input.end(),greater<int>());
             input.pop_back();
             push_heap(input.begin(),input.end(),greater<int>());

        }

        return res;       
    }
};
 

JAVA

//快排
import java.util.ArrayList;
import java.util.Arrays;
public class Solution
 {
    public ArrayList<Integer> GetLeastNumbers_Solution(int [] input, int k) 
    {
        ArrayList<Integer> list=new ArrayList<>();
        if(input.length<k||k==0)
            return list;
        Arrays.sort(input);   
        for(int i=0;i<k;i++)
            list.add(input[i]);
        return list;
    }
}
 

Python

# -*- coding:utf-8 -*-
class Solution:
    def GetLeastNumbers_Solution(self, tinput, k):
        # write code here
        if tinput == None:
            return None
        l = len(tinput)
        if k > l:
            return []
        tinput = sorted(tinput)
        return tinput[:k]