快速排序算法JAVA語言Demo

import java.util.Random;


public class ArithmeticTest {
	public static void main(String[] args) {
		ArithmeticTest test = new ArithmeticTest();
		int[] arr1=new int[5];
		for(int i=0;i<arr1.length;i++){
			arr1[i]=new Random().nextInt(100)+1;
		}
		for(int i=0;i<arr1.length;i++){
			System.out.print(arr1[i] + "  ");
		}
		System.out.println();
		long a=System.currentTimeMillis();
		test.quickSort(arr1, 0, arr1.length-1);
		for(int i=0;i<arr1.length;i++){
			System.out.print(arr1[i] + "  ");
		}
		long b=System.currentTimeMillis();
		System.out.println();
		System.out.println("快速排序耗時："+(b-a)+"ms");
	}
	
	public void quickSort(int[] arr,int head,int tail){
		int i=head;
		int j=tail;
		if(i > j){
			return;
		}
		int key=arr[i];
		while(i<j){
			while(i<j && key<=arr[j]){
				j--;
			}
			if(i<j){
				arr[i++]=arr[j];
			}
			while(i<j && key>=arr[i]){
				i++;
			}
			if(i<j){
				arr[j--]=arr[i];
			}
		}
		arr[j]=key;
		quickSort(arr,head,j-1);
		quickSort(arr,j+1,tail);
		
	}
}