数据结构及算法之队列（基于链表）讲解

傷城~ 2024-04-18 23:21 12阅读 0赞

1，具体实现

<table> 
 <tbody> 
  <tr> 
   <td> <pre><code>package com.dream21th.algorithmicdatastructure.linkedlist;

/**
 * @Auther: hp
 * @Date: 2019/9/13 20:52
 * @Description:
 */
public class LinkedListQueue&lt;E&gt; implements Queue&lt;E&gt; {

private class Node{

public E e;

public Node next;

public Node(E e,Node next) {
            this.e = e;
            this.next = next;
        }

public Node(E e){
            this(e,null);
        }

public Node(){
            this(null,null);
        }

@Override
        public String toString() {
            return e.toString();
        }
    }

private Node head;
    private Node tail;
    private int size;

public LinkedListQueue(){
        head=null;
        tail=null;
        size=0;
    }
    @Override
    public int getSize() {
        return size;
    }

@Override
    public void enquene(E e) {

if(tail==null){
            tail=new Node(e);
            head=tail;
        }else {
            tail.next=new Node(e);
            tail=tail.next;
        }
        size++;
    }

@Override
    public E dequene() {
        if(isEmpty()){
            throw new IllegalArgumentException("illeage operator");
        }
        Node current = this.head;
        head=head.next;
        current.next=null;
        if(head==null){
            tail=null;
        }
        size--;
        return current.e;
    }

@Override
    public E getfornt() {
        if(isEmpty()){
            throw new IllegalArgumentException("illeage operator");
        }
        return head.e;
    }

@Override
    public boolean isEmpty() {
        return size==0;
    }

@Override
    public String toString() {

StringBuilder builder=new StringBuilder();

builder.append("Queue head");
        builder.append("[");

for(Node cur=head;cur!=null;cur=cur.next){
            builder.append(cur+"-&gt;");
        }
        builder.append("Null ] tail");
        return builder.toString();
    }

public static void main(String[] args) {
        LinkedListQueue&lt;Integer&gt; linkedListStack = new LinkedListQueue&lt;&gt;();

for(int i=0;i&lt;10;i++){
            linkedListStack.enquene(i);
        }
        linkedListStack.dequene();
        linkedListStack.dequene();
        System.out.println(linkedListStack);
    }
}
</code></pre> </td> 
  </tr> 
 </tbody> 
</table>