循环链表实现队列

Posted 2022-12-03 ssdut_yrp

public class Link 
    public long lData;
    public Link next;

    public Link(long lData)
        this.lData=lData;
    

    public void displayLink()
        System.out.print(lData+" ");
    

public class CircleList 
    private Link current;
    private int nItems;

    public CircleList()
        current=null;
    

    public void insert(long value)
        Link newLink = new Link(value);
        if(current==null)
            current=newLink;
            newLink.next=newLink;
        else
            newLink.next=current.next;
            current.next=newLink;
            current=newLink;//插入元素，current要移动要新元素
        
        nItems++;
    

    public long remove()
        long temp = current.next.lData;
        if(current.next==current)
            current=null;
        else
            current.next=current.next.next;
        
        nItems--;
        return temp;
    

    public long peek()
        return current.next.lData;
    

    public Link find(long value)
        Link temp =current;
        Link result=null;
        if(current==null)
            return result;
        
        do
            step();//从current的下一个元素开始
            if(current.lData==value)
                result=current;
                current=temp;//还原current到原来的位置，这样就不会打乱插入的顺序，current指向最后插入的元素
            
        while(current!=temp);//current到原来的位置，一周循环结束
        return result;
    

    public void step()
        if(current!=null)
            current=current.next;// 调用step()方法后，顺序会被打乱
        
    

    public void display()
        if(current!=null)
            Link temp =current;
            do
                step();// 从current的一下个开始显示
                System.out.print(current.lData + " ");
            while(current!=temp);
        
        System.out.println();
    

    public boolean isEmpty()
        return (current==null);
    

    public int size()
        return nItems;
    

public class Queue 
    private CircleList theCircleList;
    private int nItems;

    public Queue()
        theCircleList = new CircleList();
        nItems=0;
    

    public void insert(long value)
        theCircleList.insert(value);
    

    public long remove()
        return theCircleList.remove();
    

    public long peek()
        return theCircleList.peek();
    

    public boolean isEmpty()
        return (theCircleList.size()==0);
    

    public int size()
        return theCircleList.size();
    

    public void display()
        theCircleList.display();
    

public class QueueApp 
    /**
     * @param args
     */
    public static void main(String[] args) 
        // TODO Auto-generated method stub
        Queue newQueue = new Queue();
        newQueue.insert(10);
        newQueue.insert(20);
        newQueue.insert(30);
        newQueue.insert(40);
        newQueue.display();
        newQueue.remove();
        newQueue.remove();
        newQueue.display();
        newQueue.insert(50);
        newQueue.insert(60);
        newQueue.insert(70);
        newQueue.display();
        long n = newQueue.remove();
        System.out.println("删掉："+n);
        System.out.println("队头元素是"+newQueue.peek());
        newQueue.display();