使用带 head 头的单向链表实现

package com.example.dataStructureAndAlgorithm.LinkedList;

public class SingleLinkedListDemo {
    public static void main(String[] args) {
        Node node1=new Node(1,"1");
        Node node2=new Node(2,"2");
        Node node3=new Node(3,"3");
        Node node4=new Node(4,"4");
        SingleLinkedList singleLinkedList=new SingleLinkedList();
//        singleLinkedList.addNode(node1);
//        singleLinkedList.addNode(node3);
//        singleLinkedList.addNode(node2);
//        singleLinkedList.addNode(node4);
        singleLinkedList.addNodeByNo(node1);
        singleLinkedList.addNodeByNo(node3);
        singleLinkedList.addNodeByNo(node2);
        singleLinkedList.addNodeByNo(node4);
  //      singleLinkedList.update(new Node(5,"222"));
        singleLinkedList.show();
        System.out.println("删除后");
        singleLinkedList.delete(1);
        singleLinkedList.delete(4);
        singleLinkedList.show();
    }
}

class SingleLinkedList {
    private Node head = new Node(0, "");

    public void addNode(Node node) {
        Node temp = head;
        while (true) {
            if (temp.next == null) {//说明找到了链表的末尾，将最后这个节点的next指向要添加的节点，退出循环
                temp.next = node;
                return;
            }
            temp = temp.next;//如果没有找到链表的末尾，则将temp后移
        }
    }

    /***
     * 添加节点，考虑编号顺序
     * @param node
     */
    public void addNodeByNo(Node node){
       boolean flag=false;
        Node temp=head;
        while (true){
            if (temp.next==null){//说明temp已经在链表的末尾，直接添加到temp后面
                break;
            }else if (temp.next.no>node.no){//temp的下一个节点的no>node.no,说明找到要添加的位置，插入到temp的后面
                break;
            }else if (temp.next.no==node.no){//说明要添加的节点编号已经存在
                flag=true;
                break;
            }
            temp=temp.next;//temp后移，遍历链表
        }
        if (flag){
            System.out.println("此编号节点已存在");
        }else {
            //插入到链表中, temp 的后面
            node.next=temp.next;
            temp.next=node;

        }

    }
    public void update(Node node){
        Node temp=head;
        if (temp.next!=null){
            boolean flag=false;
            while (true){
                if (temp.next==null){
                    break;
                }
                if (temp.next.no==node.no){
                    flag=true;
                    break;
                }
                temp=temp.next;
            }
            if (flag){
                temp.next.name=node.name;
            }else {
                System.out.println("未找到相关编号节点");
            }

        }else
        System.out.println("链表为空");
    }

    public void delete(int no){
        if (head.next==null){
            System.out.println("链表为空");
        }
        Node temp=head;
        boolean flag=false;
        while (true){
            if (temp.next==null){
                break;
            }else if (temp.next.no==no){
                flag=true;
                break;
            }
            temp=temp.next;
        }
        if (flag){
            //删除。删除temp的下一个节点就是将temp的next指向下一个节点的下一个
            temp.next=temp.next.next;
        }else {
            System.out.println("未找到编号节点");
        }
    }
    public void show() {
        if (head.next == null) {
            System.out.println("链表为空");
            return;
        }
        Node temp = head.next;
        while (true) {
            if (temp.next == null) {
                System.out.println(temp);
                return;
            }
            System.out.println(temp);
            temp = temp.next;
        }
    }
}

class Node {
    public int no;
    public String name;
    Node next;

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

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

本文地址：https://blog.csdn.net/Paranoid_94/article/details/109579193