数据结构和算法四：双向链表

package com.atguigu.linkedlist;

public class DoubleLinkedListDemo {

    public static void main(String[] args) {
        System.out.println("------------双向链表的测试-------------");
        HeroNode2 hero1 = new HeroNode2(1, "松江", "及时雨");
        HeroNode2 hero2 = new HeroNode2(2, "卢俊义", "玉麒麟");
        HeroNode2 hero3 = new HeroNode2(3, "吴用", "智多星");
        HeroNode2 hero4 = new HeroNode2(4, "林冲", "豹子头");

        DoubleLinkedList doubleLinkedList = new DoubleLinkedList();
        doubleLinkedList.add(hero1);
        doubleLinkedList.add(hero2);
        doubleLinkedList.add(hero3);
        doubleLinkedList.add(hero4);

        System.out.println("------------输出-------------");
        doubleLinkedList.list();

        System.out.println("------------修改-------------");
        HeroNode2 hero5 = new HeroNode2(4, "林冲冲啊", "豹子头");
        doubleLinkedList.update(hero5);
        doubleLinkedList.list();

        System.out.println("------------删除-------------");
        doubleLinkedList.delete(hero2);
        doubleLinkedList.list();

        System.out.println("------------按序添加-------------");
        doubleLinkedList.addByNo(hero2);
        doubleLinkedList.list();

    }

}

//创建一个双向链表类
class DoubleLinkedList {
    //定义头节点
    private HeroNode2 head = new HeroNode2(0, "", "");

    public HeroNode2 getHead() {
        return head;
    }

    /**
     * 按照标号进行添加
     * @param heroNode2
     */
    public void addByNo(HeroNode2 heroNode2) {
        HeroNode2 temp = head;
        boolean flag = false;
        while (true) {
            if (temp.next == null) {
                break;
            }
            if (temp.next.no > heroNode2.no) {
                flag = true;
                break;
            } else if (temp.next.no == heroNode2.no) {
                break;
            }
            temp = temp.next;
        }
        if (flag) {
            heroNode2.next = temp.next;
            heroNode2.pre = temp;
            if (temp.next != null) {
                temp.next.pre = heroNode2;
            }
            temp.next = heroNode2;
        } else {
            System.out.println("该节点已经存在，添加失败");
        }
    }

    /**
     * 删除一个节点
     * @param heroNode
     */
    public void delete(HeroNode2 heroNode) {
        HeroNode2 temp = head.next;
        boolean flag = false;
        while (true) {
            if (temp == null) {
                break;
            }
            if (temp.no == heroNode.no) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag) {
            temp.pre.next = temp.next;
            if (temp.next != null) {
                temp.next.pre = temp.pre;
            }
        } else {
            System.out.println("未找到目标节点，删除失败");
        }
    }


    /**
     * 修改一个节点
     * @param heroNode
     */
    public void update(HeroNode2 heroNode) {
        HeroNode2 temp = head.next;
        boolean flag = false;
        while (true) {
            if (temp == null) {
                break;
            }
            if (temp.no == heroNode.no) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag) {
            heroNode.pre = temp.pre;
            heroNode.next = temp.next;
            temp.pre.next = heroNode;
            if (temp.next != null) {
                temp.next.pre = heroNode;
            }
        } else {
            System.out.println("未找到目标节点，更新失败");
        }
    }

    /**
     * 添加节点到链表尾部
     * @param heroNode
     */
    public void add(HeroNode2 heroNode) {
        //保存头节点
        HeroNode2 temp = head;
        //遍历链表，找到最后一个节点
        while (true) {
            if (temp.next == null) {
                break;
            }
            temp = temp.next;
        }
        //循环跳出时，temp指向最后一个节点，然后将新节点添加即可
        temp.next = heroNode;
        heroNode.pre = temp;
    }

    /**
     * 显示链表
     */
    public void list() {
        //判断链表是否为空
        if (head.next == null) {
            System.out.println("链表为空");
            return;
        }
        HeroNode2 temp = head.next;
        while (true) {
            //判断是否到链表最后
            if (temp == null) {
                break;
            }
            System.out.println(temp);
            temp = temp.next;
        }

    }
}


//定义HeroNode
class HeroNode2 {
    public int no;
    public String name;
    public String nickName;
    public HeroNode2 next;
    public HeroNode2 pre;

    public HeroNode2(int no, String name, String nickName) {
        this.no = no;
        this.name = name;
        this.nickName = nickName;
    }


    @Override
    public String toString() {
        return "HeroNode2{" +
                "no=" + no +
                ", name='" + name + '\'' +
                ", nickName='" + nickName + '\'' +
                '}';
    }
}