2021-11-05Java实现快速排序

package com.atguigu.Sort;

import java.util.Arrays;


public class QuickSort {
    public static void main(String[] args) {
//        int[] arr = {8,9,1,7,2,3,5,4,6,0};
        int[] arr = new int[8000000];
        for(int i = 0;i < 8000000;i++){
            arr[i] = (int)(Math.random()*(8000000 - 0 + 1));
        }
        long start = System.currentTimeMillis();
        quick_sort(arr,0,arr.length-1);
        long end = System.currentTimeMillis();
        System.out.println("花费时间为：" + (end - start));
//        System.out.println(Arrays.toString(arr));
    }

    public static void quick_sort(int[] arr,int start,int end){
        if(start > end)
            return;
        int temp = arr[start];
        int i = start;
        int j = end;
        while (i!=j){
            while (arr[j] >= temp && j > i){
                j--;
            }
            while(arr[i] <= temp && j > i){
                i++;
            }
            if(j > i){
                int t = arr[i];
                arr[i] = arr[j];
                arr[j] = t;
            }
        }
        arr[start] = arr[i];
        arr[i] = temp;
        quick_sort(arr, start, i-1);
        quick_sort(arr, i+1, end);
            }
        }