Java--算法--双向链表

1. 双向链表创建：
   1. 

2. 双向链表的实际应用：

   1. 

3. package com.model.linkedlist.doubly;
   
   /**
    * @Description:测试类
    * @Author: 张紫韩
    * @Crete 2021/7/9 9:57
    * 双向链表的介绍
    */
   public class DoublyLinkedListDemo01 {
       public static void main(String[] args) {
           DoublyLinkedList list=new DoublyLinkedList();
           list.add(new Node(1,"a"));
           list.add(new Node(2,"a"));
           list.add(new Node(3,"a"));
           list.add(new Node(4,"a"));
           list.add(new Node(5,"a"));
           list.show();
           list.delete(new Node(1,"a"));
           list.show();
           list.update(new Node(2,"张紫韩"));
           list.show();
           DoublyLinkedList list1 = new DoublyLinkedList();
           list1.addInOrder(new Node(3,"a"));
           list1.addInOrder(new Node(2,"a"));
           list1.addInOrder(new Node(1,"a"));
           list1.addInOrder(new Node(4,"a"));
           System.out.println("按顺序添加节点");
           list1.show();
       }
   }
   //双向链表类
   class DoublyLinkedList{
       private Node head=new Node();
       public Node getHead() {
           return head;
       }
       //添加元素,到链表的最后端
       public void add(Node node){
           Node temp=head;
           while(true){
               if (temp.next==null){
                   break;
               }
               temp=temp.next;
           }
           temp.next=node;
           node.pre=temp;
       }
   //    按这id号的大小进行添加
       public void addInOrder(Node node){
           Node temp=head;
           boolean flag=false;//是否可以进行添加
           while(true){
               if (temp.next==null){
                   break;
               }
               if (temp.next.id>node.id){
                   break;
               }
               if (temp.next.id==node.id){
                   flag=false;
                   break;
               }
               temp=temp.next;
           }
           if (flag){
               System.out.println("已经存在此节点，不能进行重复的添加");
   
           }else {
               //判断是加在链表的最后还是链表的中间部分
               if (temp.next==null) {
                   temp.next = node;
                   node.pre = temp;
               }else {
                   node.next = temp.next;
                   node.pre = temp;
                   temp.next = node;
                   node.next.pre = node;
               }
           }
       }
       //删除元素
       public void delete(Node node){
           if (isEmpty()){
               System.out.println("链表为空不能进行删除");
               return;
           }
           Node temp=head.next;
           boolean flag=false;
           while (true){
               if (temp==null){
                   break;
               }
               if (temp.id==node.id){
                   flag=true;
                   break;
               }
               temp=temp.next;
           }
           if (flag){
               temp.pre.next=temp.next;
               temp.next.pre=temp.pre;
           }else {
               System.out.println("没有找到此节点不能进行删除");
           }
   
       }
   //    修改节点
       public void update(Node node){
           if (isEmpty()){
               System.out.println("链表为空，不能进行修改");
               return;
           }
           Node temp=head.next;
           boolean flag=false;
           while (true){
               if (temp==null){
                   break;
               }
               if (temp.id==node.id){
                   flag=true;
                   break;
               }
               temp=temp.next;
           }
           if (flag){
               temp.name=node.name;
           }else {
               System.out.println("没有找到此节点，不能进行修改");
           }
       }
   
   //    遍历链表
       public void show(){
           Node temp=head.next;
           while(true){
               if (temp==null){
                   break;
               }
               System.out.println(temp.toString());
               temp=temp.next;
           }
       }
   
       public boolean isEmpty(){
           if (head.next==null){
               return true;
           }
           return false;
       }
   
   }
   //双向链表的节点类
   class Node{
       public int id;
       public String name;
       public Node pre;
       public Node next;
   
       public Node() {
       }
   
       @Override
       public String toString() {
           return "Node{" +
                   "id=" + id +
                   ", name='" + name + '\'' +
                   '}';
       }
   
       public Node(int id, String name) {
           this.id = id;
           this.name = name;
       }
   }