题解 | #最小的K个数#

import java.util.*;

public class Solution {
    public ArrayList<Integer> GetLeastNumbers_Solution(int [] input, int k) {
        ArrayList<Integer> list = new ArrayList();
        quickSort(input,0,input.length-1);

        if(k<=input.length){
            for(int i=0;i<k;i++){
                list.add(input[i]);
            }
        }
        return list;
    }

    public void quickSort(int [] arr,int low,int high){
        int i,j,temp;

        if(low>high){
            return;
        }

        i = low;
        j = high;
        temp = arr[low];

        while(i<j){

            while(i<j && temp <= arr[j]){
                j--;
            }

            while(i<j && temp >= arr[i]){
                i++;
            }

            if(i<j){
                int tmp = arr[j];
                arr[j] = arr[i];
                arr[i] = tmp;
            }
        }

        arr[low] = arr[i];
        arr[i] = temp;

        quickSort(arr,low,i-1);
        quickSort(arr,i+1,high);
    }
}