/** * 使用链表实现队列 * Create by Administrator * 2018/6/19 0019 * 下午 4:37 **/public class Link {    public long dData;    public Link next;    public Link(long d){        this.dData = d;    }    public void displayLink(){        System.out.print(dData + " ");    }}class FirstLastList{    private Link first;    private Link last;    public FirstLastList(){        this.first = null;        this.last = null;    }    public boolean isEmpty(){        return first == null;    }    public void insertLast(long dd){        Link newLink = new Link(dd);        if(isEmpty()){            first = 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;    }    public void displayList(){        Link current = first;        while (current != null){            current.displayLink();            current = current.next;        }        System.out.println("");    }}class LinkQueue{    private FirstLastList theList;    public LinkQueue(){        this.theList = new FirstLastList();    }    public boolean isEmpty(){        return theList.isEmpty();    }    public void insert(long j){        theList.insertLast(j);    }    public long remove(){        return theList.deleteFirst();    }    public void displayQueue(){        System.out.print("Queue (front-->rear): ");        theList.displayList();    }    public static void main(String[] args) {        LinkQueue linkQueue = new LinkQueue();        linkQueue.insert(20);        linkQueue.insert(40);        linkQueue.displayQueue();        linkQueue.insert(60);        linkQueue.insert(80);        linkQueue.displayQueue();        linkQueue.remove();        linkQueue.remove();        linkQueue.displayQueue();    }}