单链表的反转

1、代码案例：

package com.zhangwl.数据结构.单链表;

/**
 * @ClassName SingleLinkedList
 * @Description
 * @Author zhangwl
 * @Date 2019/10/20 20:59
 * @Version 1.0
 **/
@SuppressWarnings("all")
public class SingleLinkedList {

    private HeroNode first = new HeroNode(0, "", "");

    /*添加节点*/
    public void add(HeroNode heroNode) {
        HeroNode tempNode = this.first;
        while (true) {
            if (null == tempNode.nextNode) {
                break;
            }
            tempNode = tempNode.nextNode;
        }
        tempNode.nextNode = heroNode;
    }

    public void update(HeroNode heroNode) {
        if (first.nextNode == null) {
            System.out.println("链表为空，尚无数据可改...");
        }
        boolean flag = false;
        HeroNode tempNode = first;
        while (true) {
            if (tempNode.nextNode == null) {
                break;//尚无找到可进行修改的节点
            }
            if (tempNode.no == heroNode.no) {
                flag = true;
                break;
            }
            tempNode = tempNode.nextNode;
        }

        if (flag) {
            tempNode.name = heroNode.name;
            tempNode.nickName = heroNode.nickName;
            return;
        }
        System.out.println("尚无找到可进行修改的节点");
    }

    public void addNode(HeroNode heroNode) {
        HeroNode tempNode = this.first;
        boolean flag = false;//表示节点是否存在
        while (true) {
            if (tempNode.nextNode == null) {
                break;
            }
            if (tempNode.nextNode.no > heroNode.no) {
                break;
            } else if (tempNode.nextNode.no == heroNode.no) {
                flag = true;
                break;
            }
            tempNode = tempNode.nextNode;
        }
        /*准备添加数据*/
        if (flag) {
            System.out.println("节点存在，无需重复添加");
            System.out.println(tempNode.nextNode);
            return;
        }
        heroNode.nextNode = tempNode.nextNode;
        tempNode.nextNode = heroNode;
    }

    /*显示所有节点*/
    public void list() {
        HeroNode tempNode = this.first;
        while (true) {
            if (tempNode == null) {
                break;
            }
            System.out.println(tempNode);
            System.out.println();
            tempNode = tempNode.nextNode;
        }
    }

    public void delete(int no) {
        HeroNode tempNode = first;
        boolean flag = false;
        while (true) {
            if (tempNode.nextNode == null) {
                break;
            }

            if (tempNode.nextNode.no == no) {
                flag = true;
                break;
            }
            tempNode = tempNode.nextNode;
        }
        if (flag) {
            tempNode.nextNode = tempNode.nextNode.nextNode;
            return;
        }
        System.out.println("目标节点不存在...");
    }

    /**
     * 反转单链表
     */
    public void reverseList() {
        //如果一个节点headNode.next为null 或 headNode.next.next 为null 无需翻转
        if (first.nextNode == null || first.nextNode.nextNode == null) {
            return;
        }

        //临时节点,记录
        HeroNode tempNode = first.nextNode;
        //临时存放下一个节点的节点
        HeroNode nextNode = null;
        //创建一个反转的头节点
        HeroNode reverseNode = new HeroNode(0, "", "");
        //循环判断节点是否为空
        while (tempNode.nextNode != null) {
            nextNode = tempNode.nextNode;
            tempNode.nextNode = reverseNode.nextNode;
            reverseNode.nextNode = tempNode;
            tempNode = nextNode;
        }

        tempNode.nextNode = reverseNode.nextNode;
        reverseNode.nextNode = tempNode;
        first.nextNode = reverseNode.nextNode;
    }
}

package com.zhangwl.数据结构.单链表;

import org.junit.Test;

/**
 * @ClassName MainTest
 * @Description
 * @Author zhangwl
 * @Date 2019/11/17 21:23
 * @Version 1.0
 **/
public class MainTest {

    /**
     * 测试队列反转
     */
    @Test
    public void test_01() {
        SingleLinkedList linkedList = new SingleLinkedList();
        linkedList.addNode(new HeroNode(1, "1", "1"));
        linkedList.addNode(new HeroNode(2, "2", "2"));
        linkedList.addNode(new HeroNode(3, "3", "3"));
        linkedList.addNode(new HeroNode(5, "5", "5"));
        linkedList.addNode(new HeroNode(4, "4", "4"));
        //展示数列
        System.out.println("***********************************原数列***********************************");
        linkedList.list();
        System.out.println();
        //反转数列
        linkedList.reverseList();
        System.out.println("***********************************反转后的数列***********************************");
        linkedList.list();
        System.out.println();
    }
}

2、运行结果：

***********************************原数列***********************************
HeroNode{no=0, name='', nickName=''}

HeroNode{no=1, name='1', nickName='1'}

HeroNode{no=2, name='2', nickName='2'}

HeroNode{no=3, name='3', nickName='3'}

HeroNode{no=4, name='4', nickName='4'}

HeroNode{no=5, name='5', nickName='5'}

***********************************反转后的数列***********************************
HeroNode{no=0, name='', nickName=''}

HeroNode{no=5, name='5', nickName='5'}

HeroNode{no=4, name='4', nickName='4'}

HeroNode{no=3, name='3', nickName='3'}

HeroNode{no=2, name='2', nickName='2'}

HeroNode{no=1, name='1', nickName='1'}