Question

我尝试使用基于数组的堆实现优先级队列。到目前为止，我的堆类看起来像这样

public class ArrayHeap<E> 
{
    private Node<E>[] data; //Array to hold nodes
    private int capacity; //Length to make the array
    private int dataCount; //Current number of elements

    /**
     * Constructor for heap
     * @param passedCapacity
     */
    public ArrayHeap(int passedCapacity)
    {
        this.capacity = passedCapacity;
        this.dataCount = 0;
        data = new Node[capacity];
    }

    public void insert(Node<E> value) 
    {
        data[dataCount] = value;
        trickleUp(dataCount++);
    }    

    /**
     * Method to slide inserted data to correct position.
     * Based on Data Structures & Algorithms in Java, 2nd Edition (pg. 593)
     */
    private void trickleUp(int index)
    {
        int parent = index-1 / 2;
        Node<E> bottom = data[index];
        while(index > 0 && data[parent].getPriority() < bottom.getPriority())
        {
            data[index] = data[parent];
            index = parent;
            parent = (parent-1) / 2;
        }
        data[index] = bottom;
    }

    public E remove()
    {
        return null;
    }

    public void print()
    {
        for(int i = 0; i < dataCount; i++)
        {
            System.out.println(data[i].getPriority() + ": " + data[i].getData());
        }
        System.out.println("Total nodes: " + dataCount);
    }
}

我的优先级队列看起来像这样

public class PriorityQueue<E> implements PriQue<E>
{
    private ArrayHeap<E> data;

    public PriorityQueue()
    {
        this.data = new ArrayHeap<E>(1000);
    }

    @Override
    public void insert(int pri, E dataToInsert) {
        Node<E> nodeToInsert = new Node<E>(pri, dataToInsert);
        data.insert(nodeToInsert);
    }

    public void print()
    {
        data.print();
    }
}

但是，当我将一系列节点插入队列并使用我的print语句将它们吐出来时，它们的插入顺序与它们相同。我觉得我的trickleUp方法有问题，但无法弄清楚它是什么。

Answer 1

数组中的数据不应该被排序。它是一堆。您必须连续删除一个元素并一次重新堆积一个元素以获得总排序。

优先级队列不按优先级插入内容

1 个答案: