颠倒双向链表的整个列表的顺序

Question

我正在阅读 java 实现中的队列。我要执行以下任务：

public class DoublyLinkedList
{
    private Node first; // the first Node in the list
    private Node last; // the last Node in the list  

    private class Node
    {
        private Point p;
        private Node prev; // the previous Node
        private Node next; // the next Node
    }  

    public void reverse()
    {
        // your code
    }
}

我喜欢这个：

public void reverse() { // that reverses the order of the entire list
    if (first == null && last == null) {
         throw new RuntimeException(); 
    }  

    Node current = first;
    while (current!=null) {
        current.next= current.next.prev;
        current.prev=current.prev.next;
        current=current.next;
    }  
}

我做的对吗？谢谢

Answer 1

不，不是。 current.next = current.next.prev 类似于 current.next = current，current.prev = current.prev.next 类似于 current.prev = current。请附加调试器并按照您的代码查找错误和正确的解决方案。我们不会在这里做你的功课。 ;-)

Answer 2

您没有更改代码中的第一个和最后一个指针。如果列表为空，为什么要抛出异常？

我想我会做类似的事情：

public void reverse()
{
    Node current = first;
    while (current != null) {
        Node next = current.next;
        current.next = current.prev;
        current.prev = next;
        current = next;
    }
    Node temp = first;
    first = last;
    last = temp;
}

颠倒双向链表的整个列表的顺序

reverse the order of the entire list for doubly linkedList

java

doubly-linked-list