JAVA数据结构:双端链表

双端链表与传统链表非常相似.只是新增了一个属性-即对最后一个链结点的引用

定义一个Link类

public class Link {    public long dData;    public Link next;    public Link(long d){        dData = d;    }    public void displayLink(){        System.out.println(dData+" ");    }}

双端链表的简单实现

public class FirstLastLink(){    private Link first;    private Link last;    public FirstLastLink(){        first = null;        last = null;    }    public void display(){        System.out.println("FirstLastLink: (first-->last)");        Link current = first;        while(current !=null){            current.displayLink();            current = current.next;        }        System.out.println("");    }    public boolean isEmpty(){        return (first == null);    }    public void insertFirst(long value){        Link newlink = new Link(value);        if(isEmpty()){            last = newlink;            first = newlink;        }else{            newlink.next = first;            first = newlink;        }    }    public void insertLast(long value){        Link newlink = new Link(value);        if(isEmpty()){            first = newlink;            last = newlink;        }else{            last.next = newlink;            last = newlink;        }    }    public long deleteFirst(){        long temp = first.dData;        if(first.next == null){            last = null;        }        first = first.next;        return temp;    }}

双端链表不能删除最后一个链节点,因为没有引用指向最后第二个链节点.
为了方便地删除最后一个链节点,需要一个双向链表