快速排序-使用多线程做快速排序

最新推荐文章于 2022-05-16 20:24:51 发布

ross

最新推荐文章于 2022-05-16 20:24:51 发布

阅读量1.1k

点赞数

CC 4.0 BY-SA版权

分类专栏： JAVA

本文链接：https://blog.youkuaiyun.com/fycghy0803/article/details/80177348

JAVA 专栏收录该内容

48 篇文章

订阅专栏

本文介绍了一种基于快速排序算法的并行实现方法。通过使用双线程进行分区排序，对比了单线程和多线程排序的性能差异。该实现利用了Java的并发工具类，如CountDownLatch和ExecutorService。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

package com.spark;

import org.junit.Before;
import org.junit.Test;
import scala.tools.nsc.Global;

import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * Created by fanyuli on 2018/5/2.
 */
public class TestQuickSort {
    int index = -1;
    CountDownLatch countDownLatch = new CountDownLatch(2);
    int[] data = new int[800000];

    @Before
    public void initData() {
        Random r = new Random();
        for(int i=0;i<data.length;i++) {
           data[i] = r.nextInt(100);
        }
    }

    @Test
    public void testQuickSortThread() {  //使用双线程做排序
        ExecutorService executorService = Executors.newFixedThreadPool(2);

      System.out.println(System.currentTimeMillis());

index = partition(data,0,data.length - 1); quickSortThread q1 = new quickSortThread(data,0,index - 1); quickSortThread q2 = new quickSortThread(data,index +1,data.length-1); executorService.execute(q1); executorService.execute(q2); try{ countDownLatch.await(); }catch (Exception e) { e.printStackTrace(); } for(int i=0;i < data.length;i++) { //System.out.print(data[i] + " "); } System.out.println("\r\n" + System.currentTimeMillis()); } class quickSortThread implements Runnable { int start; int end; int[] data; public quickSortThread(int[] data,int start,int end) { this.start = start; this.end = end; this.data = data; } @Override public void run() { quickSort(data,start,end); countDownLatch.countDown(); } public void quickSort(int[] data,int left,int right) { if(left >= right) return; int i = partition(data,left,right); quickSort(data,left,i - 1); quickSort(data,i + 1,right); } } @Test public void runQuickSort() { //使用单个线程做排序 System.out.println(System.currentTimeMillis()); quickSort(data,0,data.length - 1); for(int i=0;i < data.length;i++) { //System.out.print(data[i] + " "); } System.out.println("\r\n"+ System.currentTimeMillis()); } public void quickSort(int[] data,int left,int right) { if(left >= right) return; index = partition(data,left,right); quickSort(data,left,index - 1); quickSort(data,index + 1,right); } public int partition(int[] data,int left,int right) { int temp = data[left]; while(left < right) { while(temp <= data[right] && left < right){ right--; } data[left] = data[right]; while(temp > data[left] && left < right){ left++; } data[right] = data[left]; } data[left] = temp; return left; }}