03.带头结点的单链表

/**
 * 带头结点的单链表
 */
public class LinkListDemo {
    public static void main(String[] args){
        Node n1 = new Node(1,"A");
        Node n2 = new Node(2,"B");
        Node n3 = new Node(3,"C");
        Node n4 = new Node(4,"D");
//        LinkList linkList = new LinkList();
//        linkList.add(n2);
//        linkList.add(n1);
//        linkList.add(n4);
//        linkList.add(n3);
//        linkList.list();
        LinkList linkList2 = new LinkList();
        linkList2.addOrder(n2);
        linkList2.addOrder(n1);
        linkList2.addOrder(n4);
        linkList2.addOrder(n3);
        linkList2.addOrder(n3);
        linkList2.list();
        Node n44 = new Node(4,"D～");
        linkList2.update(n44);
        linkList2.list();
        System.out.println("删除");
        linkList2.del(3);
        linkList2.list();
    }
}
class LinkList{
    //头结点
    private Node head = new Node(0,"");
    private boolean addMethod = false;
    //顺序插入
    public void add(Node node){
        this.addMethod = true;
        Node temp = head;
        //找尾结点
        while (true){
            if (temp.next==null){
                break;
            }
            temp = temp.next;
        }
        temp.next = node;
    }
    //有序插入 根据no
    public void addOrder(Node node){
        if (addMethod){
            System.out.println("有序插入不能与add()调用后使用!");
            return;
        }
        Node temp = head;
        boolean flag = false; //重复的no
        while (true){
            if (temp.next==null){
                break;
            }else if (temp.next.no == node.no){
                flag = true;
                System.out.println("存在重复的Node");
                break;
            }else if (temp.next.no > node.no){
                break;
            }
            temp = temp.next;
        }
        if (!flag){
          node.next = temp.next;
          temp.next = node;
        }
    }
    //修改 根据no 修改data
    public void update(Node node){
        if (head.next==null){
            System.out.println("链表为空");
            return;
        }
        Node temp = head.next;
        boolean flag  = false; //是否存在该节点
        while (true){
            if (temp == null){
                break;
            }
            if (temp.no == node.no){
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag){
            temp.data = node.data;
        }else {
            System.out.println("不存在该结点,不能修改");
        }
    }
    //根据no删除结点
    public void del(int no){
        Node temp = head;
        boolean flag  = false; //是否存在该结点
        while (true){
            if (temp.next == null){
                break;
            }
            if (temp.next.no == no){
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag){
            temp.next = temp.next.next;
        }else {
            System.out.println("不存在该结点,不能删除");
        }
    }
    //显示单链表
    public void list(){
        if (head.next==null){
            System.out.println("链表为空");
            return;
        }
        Node temp = head.next;
        while (true){
            if (temp!=null){
                System.out.println(temp);
                temp = temp.next;
            }else {
                break;
            }
        }
    }
}
class Node{
    public int no;
    public String data;
    public Node next;

    public Node(int no, String data) {
        this.no = no;
        this.data = data;
    }
    @Override
    public String toString() {
        return "Node{" +
                "no=" + no +
                ", data='" + data + '\'' +
                '}';
    }
}

原文地址：https://www.cnblogs.com/fly-book/p/11630969.html