快速排序

快速排序

/**
 * Created by kqq on 2018/3/24.
 */
public class QuickSort {
    public int partition(int arr[],int low,int high){
        int key=arr[low];
        while(low<high){
            while(arr[high]>key && low<high){
                high--;
            }
            arr[low]=arr[high];
            while(arr[low]<=key && low<high){
                low++;
            }
            arr[high]=arr[low];
        }
        arr[high]=key;
        return high;
    }
    public void sort(int arr[],int low,int high){
        if(low>=high){
            return;
        }
        int index=partition(arr,low,high);
        sort(arr,low,index-1);
        sort(arr,index+1,high);
    }


    //生成随机数
    public static int[] generateRandoamArray(){
        int length=(int) (Math.random()*20)+5;
        int[] arr=new int[length];
        for(int i=0;i<arr.length;i++){
            arr[i]=(int)(Math.random()*20)+1;
        }
        return arr;

    }

    public static void main(String[] args){
        QuickSort quickSort=new QuickSort();
        int testTime=5;
        for(int i=0;i<testTime;i++){
            int arr[]=generateRandoamArray();
            quickSort.sort(arr,0, arr.length-1);

        }
    }
}