数据结构之循环队列

循环队列是首位相连的一种队列，它也是一种受限的队列，队列遵守先进先出原则

java实现循环队列

Node实现类

package MyCycleQueue;

public class Node {
    private Object data;
    private Node next;
    private Node before;


    public Node(){}
    public Node(Object data){
        super();
        this.data = data;

    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }

    public Node getNext() {
        return next;
    }

    public void setNext(Node next) {
        this.next = next;
    }

    public Node getBefore() {
        return before;
    }

    public void setBefore(Node before) {
        this.before = before;
    }
}

MyCycleQueue实现类

package MyCycleQueue;

import MyStack.MyLinkStack;

public class MyCycleQueue {
    private Node root;
    private Node rear;
    private Node front;
    private int maxsize;
    private int size;


    // push
    public void push(Object data){
        Node node = new Node();
        if (front ==rear && size==0){
            root = new Node(data);
            front = root;
            rear = node;
            root.setNext(rear);
            rear.setNext(front);
            next = node;
            size ++;
        }else {
            rear.setData(data);
            rear.setNext(node);
            rear = node;
            rear.setNext(root);
            next =node;
            size ++;

        }
    }

    // pop
    public Object pop() throws Exception {
        if (root == front && size !=0){
            Object data = front.getData();
            front = root.getNext();
            size--;
            return data;
        }else if (size ==0){
            throw new Exception("队列为空");
        }else {
            Object data = front.getData();
            front = front.getNext();
            size--;
            return data;
        }
    }

}

测试类Test

package MyCycleQueue;

public class test {
    public static void main(String[] args) throws Exception {
        MyCycleQueue myCycleQueue = new MyCycleQueue();
        myCycleQueue.push(1);
        myCycleQueue.push(2);
        myCycleQueue.push(3);
        myCycleQueue.push(4);
        myCycleQueue.push(5);
//        myCycleQueue.pop();
//        myCycleQueue.pop();
//        myCycleQueue.pop();
//        myCycleQueue.pop();
//        myCycleQueue.pop();
        System.out.println(myCycleQueue.pop());
        System.out.println(myCycleQueue.pop());
        System.out.println(myCycleQueue.pop());
        System.out.println(myCycleQueue.pop());
        System.out.println(myCycleQueue.pop());
        System.out.println(myCycleQueue.pop());

    }
}