Question

简单地说，我在java中开发一个代码，用于将20个大小的数组分成4个部分，其中这4个线程将一起运行以堆排序5个元素（线程1排序索引0-4，线程2排序索引5-9等等）最后将它们与合并排序技术合并在一起。合并排序工作完全正常，因此我不包括它。但堆排序功能无法提供正确的答案。线程在数组的14到19的索引中保持旋转。我在这里做错了吗？

class heapsort
{
    private static int[] a;
    private static int i;
    private static int left;
    private static int right;
    private static int largest;

   public static void maxheap(int[] a, int i,int n00,int n01) 
    {
    left = 2 * i;
        right = 2 * i + 1;
        if ((left >= n00 && left <=n01) && a[left] > a[i]) 
        {
            largest = left;
        } 
    else 
    {
            largest = i;
        }
        if ((right >= n00 && right <=n01) && a[right] > a[largest]) 
    {
            largest = right;
        }
        if (largest != i) 
    {
            int t = a[i];
            a[i] = a[largest];
            a[largest] = t;
        heapsort h1=new heapsort();
            h1.maxheap(a, largest,n00,n01);
        }
    }

}

class sorter_ss extends Thread
{

    private static int n1,n2,n;
    private static int a[];
    sorter_ss(int a0[],int i1, int i2)
    {
        a=a0; n1=i1; n2=i2; 
    }
    public void run() 
    {
    //build heap function
    int n3=(n2+n1)/2;
        for (int i = n3; i >= n1; i--) 
    {
        heapsort h1=new heapsort();
            h1.maxheap(a,i,n1,n2);
        }
//heapsort function
        for (int i = n2-1; i >= n1; i--) 
    {
            int t = a[i];
            a[i] = a[n1];
            a[n1] = t;
        heapsort h2=new heapsort();
            h2.maxheap(a,i,n1,n2);  
        }
    }

}


public class testheap
{
    public static void main(String[] args) 
    {

        int[] a2 = { 4, 1, 3, 2, 16, 9, 10, 14, 8, 7, 80, 76, 34, 23, 56, 90, 99, 321, 86, 75};
        caller(a2);

    }
    public static void caller(int a1[])
    {   int t[]=new int[100];
    System.out.println("Array is : \n");
    for (int i = 0; i < a1.length; i++) 
    {
            System.out.print(a1[i] + " ");
        }   System.out.println();

    try{
    sorter_ss s1=new sorter_ss(a1,0,4);
    sorter_ss s2=new sorter_ss(a1,5,9);
    sorter_ss s3=new sorter_ss(a1,10,14);
    sorter_ss s4=new sorter_ss(a1,15,19);
    s1.start();
    s2.start();
    s3.start();
    s4.start();
    s1.join();
    s2.join();
    s3.join();
    s4.join();
    }
    catch(InterruptedException e)
            {
                        e.printStackTrace();
                }
    System.out.println("Sorted Array is : \n");
    for (int i = 0; i < a1.length; i++) 
    {
            System.out.print(a1[i] + " ");
        }   System.out.println();
    }
}

Answer 1

您最基本的问题是您使用static来声明线程的字段。你永远不应该这样做。

sorter_ss s1=new sorter_ss(a1,0,4);
sorter_ss s2=new sorter_ss(a1,5,9);
sorter_ss s3=new sorter_ss(a1,10,14);
sorter_ss s4=new sorter_ss(a1,15,19);

基本上你的4个线程只会在15-19个索引之间运行，因为你最后设置它们。

当你解决这个问题时，请看看Fork / Join，它是专门创建的：

http://www.oracle.com/technetwork/articles/java/fork-join-422606.html

使用线程进行堆排序

1 个答案: