Java链表和链表实现的队列

链结点:在链表中,每个数据项都被包含在"链结点"(Link)中.一个链结点是某个类的对象,这个类可以叫Link.而每个Link对象中又包含着一个对下一个链结点引用的字段(通常叫next)

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链节点:

/**
 * 节点
 * 在Java中实现链表是非常简单的，每个节点都有一个值，然后把它链接到下一个节点。 
 * @author JiaoNingbo
 * 
 */
public class Node {
    int val;        //自己的值
    Node next;    //下一个值的节点
    
    public Node(int val) {
        this.val = val;
        this.next = null;
    }

    @Override
    public String toString() {
        return "[val=" + val + ", next=" + next + "]";
    }
    
}

链表类:

/**
 * 
 * @author JiaoNingbo
 *
 */
public class Stack {
    
    Node top;   //链节点
    
    //返回链表
    public Node peek() {
        if (top != null) {
            return top;
        }
        return null;
    }
    
    //取出元素
    public Node pop() {
        if (top == null) {
            return null;
        }else {
            Node temp = new Node(top.val);
            top = top.next;
            return temp;
        }
    }
    
    //添加元素
    public void push(Node node) {
        if (node != null) {
            node.next = top;
            top = node;
        }
    }

}

队列

/**
 * 队列
 * @author JiaoNingbo
 * 
 */
public class Queue {
    
    Node first,last;
    
    //存
    public void enqueue(Node n) {
        if (first == null) {
            first = n;
            last = first;
        }else {
            last.next = n;
            last = n;
        }
    }
    
    //取
    public Node dequeue() {
        if(first == null){
            return null;
        }else{
            Node temp = new Node(first.val);
            first = first.next;
            return temp;
        }   
    }

    @Override
    public String toString() {
        return "Queue [first=" + first + ", last=" + last + "]";
    }

测试类

/**
 * 测试类
 * @author JiaoNingbo
 *
 */
public class MainNode {

    public static void main(String[] args) {
        
        Stack stack = new Stack();
        
        Node n1 = new Node(1);
        Node n2 = new Node(3);
        Node n3 = new Node(8);
        Node n4 = new Node(99);
        Node n5 = new Node(66);
        
        stack.push(n3);
        stack.push(n2);
        stack.push(n1);
        stack.push(n4);
        stack.push(n5);
        
        System.out.println(n5.toString());
        System.out.println("***************");
        Node node = stack.peek();
        System.out.println(node);
        System.out.println("***************");
        Node node2 = stack.pop();
        System.out.println(node2);
        Node node3 = stack.pop();
        System.out.println(node3);
        
    }
}

image.png

public class MainQueue {
    
    public static void main(String[] args) {
        
        Node n1 = new Node(9);
        Node n2 = new Node(7);
        Node n3 = new Node(11);
        Node n4 = new Node(16);
        
        Queue queue = new Queue();
        
        queue.enqueue(n4);
        queue.enqueue(n3);
        queue.enqueue(n2);
        queue.enqueue(n1);
        
        System.out.println(queue);
        
        Node node = queue.dequeue();
        Node node1 = queue.dequeue();
        Node node2 = queue.dequeue();
        Node node3 = queue.dequeue();
        System.out.println(node);
        System.out.println(node1);
        System.out.println(node2);
        System.out.println(node3);
        
    }

}

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若有不足之处还望大家指正(๑╹◡╹)ﾉ"""