Java 单链表 Java实现单链表SingleLinkedList增删改查及反转 逆序等

//节点类
class Node {
    public int id;
    public String name;
    public Node next;

    public Node(int id, String name) {
        this.id = id;
        this.name = name;
    }

    @Override
    public String toString() {
        return "Node{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

//链表类（管理节点）
class LinkedList {
    //头节点
    Node head = new Node(0,null);

    //链表有效数据个数（链表长度）（头节点不计）
    public int size(){
        Node temp = head;
        int size = 0;
        while (true){
            if (temp.next == null){
                break;
            }
            size++;
            temp = temp.next;
        }
        return size;
    }

    //展示链表
    public void list(){
        if (head.next == null){
            System.out.println("链表为空！");
            return;
        }
        Node temp = head.next;
        while (true){
            if (temp == null){
                break;
            }
            System.out.println(temp);
            temp = temp.next;
        }
    }

    //增(根据id从小到大)
    public void add(Node newNode){
        Node temp = head;
        while (true){ //用来找到链表尾
            if (temp.next == null) {
                break;
            }
            if (temp.id == newNode.id){
                System.out.println("要添加的节点的id已经存在，添加失败！");
                return;
            }
            if (temp.next.id > newNode.id){
                break;
            }
            temp = temp.next;
        }
        Node node = newNode;
        newNode.next = temp.next;
        temp.next = node;
    }

    //删(根据id匹配删除)
    public void remove(int id){
        if (head.next == null){
            System.out.println("链表为空!");
            return;
        }
        Node temp = head;
        boolean flag = false; //用来标记是否找到对应id的节点
        while (true){
            if (temp.next == null){
                break;
            }
            if (temp.next.id == id){ //找到要删除节点的前一个节点
                flag =true;
                break;
            }
            temp = temp.next;
        }
        if (flag){
            temp.next = temp.next.next;
        }else {
            System.out.println("没有找到要删除的节点，删除失败!");
        }
    }

    //改（根据id匹配要修改的节点）
    public void update(int id,String name){
        if (head.next == null){
            System.out.println("链表为空！");
            return;
        }
        Node temp = head;
        boolean flag = false; //用来标记是否找到对应id的节点
        while (true){
            if (temp.next == null){
                break;
            }
            if (temp.id == id){
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag){
            temp.name = name;
        }else {
            System.out.println("没有找到要修改的节点，修改失败！");
        }
    }

    //查（根据id匹配）
    public Node show(int id){
        if (head.next == null){
            System.out.println("链表为空！");
            return null;
        }
        Node temp = head.next;
        boolean flag = false;
        while (true){
            if (temp == null){
                break;
            }
            if (temp.id == id){
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag){
            return temp;
        }else {
            System.out.println("没有找到要查找的节点，查找失败！");
            return null;
        }
    }

    //查找倒数第n个节点
    public Node lastShow(int n){
        Node temp = head.next;
        int size = this.size();
        if (size < n || n <= 0){
            System.out.println("查找的节点不存在！");
            return  null;
        }
        for (int i = 0; i < size - n; i++) {
            temp = temp.next;
        }
        return temp;
    }

    //链表反转
    public void reverse(){
        if (head.next == null || head.next.next == null){
            return;
        }
        Node reverseHead = new Node(0,null);
        Node cur = head.next; //记录当前遍历到的节点
        Node next = null; //记录当前遍历到的节点的下一个节点
        while (true){
            if (cur == null){ //确保遍历到最后一个
                break;
            }
            next = cur.next; //保存下一个节点，避免断链
            //使得反转头节点指向遍历到的当前节点，而让遍历到的当前节点指向反转头节点的下一个节点
            // 确保遍历到的当前节点始终位于反转头节点的下一个
            cur.next = reverseHead.next;
            reverseHead.next = cur;
            //遍历
            cur = next;
        }
        head.next = reverseHead.next; //最后让原头节点指向反转头节点的下一个节点，即可实现原链表的反转
    }

    //逆序打印
    //方法一：先反转
    //方法二：使用栈结构
    public void reversePrint(){
        if (head.next == null){
            System.out.println("链表为空！");
            return;
        }
        Stack<Node> nodes = new Stack<>();
        Node temp = head.next;
        while (true){
            if (temp == null){
                break;
            }
            nodes.push(temp);
            temp = temp.next;
        }
        while (nodes.size() > 0){
            System.out.println(nodes.pop());
        }
    }
}

import java.util.Stack;

/**
 * @Author: Yeman
 * @Date: 2021-10-14-12:55
 * @Description:
 */
//测试类
public class SingleLinkedListTest {
    public static void main(String[] args) {

        LinkedList linkedList = new LinkedList();

        Node node1 = new Node(1, "阿兰");
        Node node2 = new Node(2, "洛国富");
        Node node3 = new Node(3, "艾克森");

		//可以不按照id顺序添加
        linkedList.add(node1);
        linkedList.add(node3);
        linkedList.add(node2);

        linkedList.list();

        System.out.println(linkedList.size()); //链表长度

//        System.out.println(linkedList.lastShow(2)); //倒数查找

//        linkedList.update(2,"张玉宁"); //改
//
//        linkedList.remove(3); //删
//
//        System.out.println(linkedList.show(2)); //查

//        linkedList.reverse(); //链表反转

        linkedList.reversePrint(); //逆序打印
        
    }
}