并行冒泡排序被阻塞的问题可能是由于不正确的线程同步导致的。下面是一种解决方法,使用Java的并发工具类来实现线程同步,并避免阻塞。
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
public class ParallelBubbleSort {
private int[] array;
private int numThreads;
private CyclicBarrier barrier;
public ParallelBubbleSort(int[] array, int numThreads) {
this.array = array;
this.numThreads = numThreads;
this.barrier = new CyclicBarrier(numThreads);
}
public void sort() {
for (int i = 0; i < array.length - 1; i++) {
for (int j = 0; j < array.length - 1 - i; j++) {
int threadIndex = j % numThreads;
Thread thread = new Thread(new BubbleSortRunnable(j, threadIndex));
thread.start();
}
// 等待所有线程完成一轮冒泡排序
try {
barrier.await();
} catch (InterruptedException | BrokenBarrierException e) {
e.printStackTrace();
}
}
}
private class BubbleSortRunnable implements Runnable {
private int index;
private int threadIndex;
public BubbleSortRunnable(int index, int threadIndex) {
this.index = index;
this.threadIndex = threadIndex;
}
@Override
public void run() {
if (array[index] > array[index + 1]) {
int temp = array[index];
array[index] = array[index + 1];
array[index + 1] = temp;
}
// 等待其他线程完成排序
try {
barrier.await();
} catch (InterruptedException | BrokenBarrierException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
int[] array = {5, 2, 9, 1, 3};
int numThreads = 3;
ParallelBubbleSort sorter = new ParallelBubbleSort(array, numThreads);
sorter.sort();
for (int num : array) {
System.out.print(num + " ");
}
}
}
在上述代码中,使用CyclicBarrier类来实现线程同步。每个线程在进行冒泡排序之后,调用barrier.await()方法等待其他线程完成排序。当所有线程都完成排序后,继续下一轮的排序。这样可以确保每个线程都能够按照正确的顺序执行,避免冒泡排序被阻塞。
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