数据结构之双项链表的操作

前面给出了单项链表的CRUD等操作,下面是对双向链表的一些操作

package com.ebiz.list;

/**
 * @author YHj
 * @create 2019-07-17 16:48
 */
public class DoubleListDemo {

    public static void main(String[] args) {

        //创建节点
        HeroNode heroNode01 = new HeroNode(1, "宋江", "及时雨");
        HeroNode heroNode02 = new HeroNode(2, "卢俊义", "玉麒麟");
        HeroNode heroNode03 = new HeroNode(3, "无用", "智多星");
        HeroNode heroNode04 = new HeroNode(4, "林冲", "豹子头");

        //创建双向链表
        DoubleList doubleList = new DoubleList();
        //添加节点
        doubleList.add(heroNode01);
        doubleList.add(heroNode02);
        doubleList.add(heroNode03);
        doubleList.add(heroNode04);

        //遍历节点
        doubleList.list(doubleList);

        //修改节点
        doubleList.update(new HeroNode(3,"有用","梦想"));
        System.out.println("修改节点之后遍历----------------------------------------------");
        doubleList.list(doubleList);

        //删除节点
        System.out.println("删除节点----------------------------------------------------");
        doubleList.del(4);
        doubleList.list(doubleList);
    }


}

//链表类
class DoubleList{

    //初始化头结点
    private  HeroNode head = new HeroNode(0, "", "");

    // 遍历节点
    public void list(DoubleList doubleList) {
        //判断是否为空
        if (null == doubleList.head.next) {
            System.out.println("链表为空");
        }
        //临时节点
        HeroNode temp = head.next;
        while (true) {
            if (null == temp) {
                break;
            }
            System.out.println("temp = " + temp);
            temp = temp.next;
        }
    }

    //新增一个节点
    public void add(HeroNode heroNode) {
        //临时节点
        HeroNode temp = head;
        //找到最后一个节点
        while (true) {
            if (temp.next == null) {
                break;
            }
            temp = temp.next;
        }
        //while循环退出,找到最后一个节点,添加新节点
        temp.next = heroNode;
        heroNode.pre=temp;
    }

    //修改对应节点
    public void update(HeroNode heroNode) {
        //临时节点
        HeroNode temp = head;
        //boolean 判断链表中是否存在对应节点
        boolean isExist = false;

        while (true) {
            if (null == temp) {
                break;
            }
            if (temp.no == heroNode.no) {
                isExist = true;
                break;
            }
            temp = temp.next;
        }
        if (isExist) {
            temp.name = heroNode.name;
            temp.nickname = heroNode.nickname;
        } else {
            System.out.println("没有对应英雄!!!");
        }
    }

    //删除一个节点
    public  void del(int no){
        if (null == head.next){
            System.out.println("链表为空,无法删除!");
        }
        //定义标识符
        boolean isExist=false;
        //定义临时节点
        HeroNode temp=head.next;
        while (true){
            if (null == temp){
                break;
            }
            if (temp.no == no){
                isExist = true;
                break;
            }
            temp =temp.next;
        }
        if (isExist){
            temp.pre.next = temp.next;
            //当前节点为最后一个节点的话  还执行这个回报空指针异常
            if (null != temp.next){
                temp.next.pre = temp.pre;
            }
        }else {
            System.out.println("没有该节点!");
        }
    }

}



//节点类
class HeroNode {
    public int no;//英雄编号
    public String name;//英雄的名字
    public String nickname;//英雄的名称
    public HeroNode next;//下一个英雄节点
    public HeroNode pre;//上一个英雄节点


    //构造器
    public HeroNode(int no, String name, String nickname) {
        this.no = no;
        this.name = name;
        this.nickname = nickname;
    }

    @Override
    public String toString() {
        return "HeroNode{" +
                "no=" + no +
                ", name='" + name + '\'' +
                ", nickname='" + nickname + '\'' +
                '}';
    }
}