题解 | #【模板】链表#

import java.util.*;

public class Main {
    static class ListNode{
        public int val;
        ListNode next;
        public ListNode(int val){
            this.val=val;
        }
    }
    static ListNode head=new ListNode(-1); 
    public static void insert(int x,int y){
        ListNode node=head;
        boolean flag=true;
        while(node.next!=null){
            if(node.next.val==x){
                ListNode n=new ListNode(y);
                n.next=node.next;
                node.next=n;
                flag=false;
                break;
            }else{
                node=node.next;
            }
        }
        if(flag){
            node.next=new ListNode(y);
        }
    }
    public static void delete(int x){
        ListNode node=head;
        while(node.next!=null){
            if(node.next.val==x){
                node.next=node.next.next;
                break;
            }else{
            node=node.next;
            }
        }
    }
    public static void main(String[] args){
        Scanner in=new Scanner(System.in);
        String str=in.nextLine();
        while(in.hasNextLine()){
            String[] s=in.nextLine().split(" ");
            if(s[0].equals("insert")){
                insert(Integer.parseInt(s[1]),Integer.parseInt(s[2]));
            }else{
                delete(Integer.parseInt(s[1]));
            }
        }
        ListNode node=head;
        if(node.next==null){
            System.out.print("NULL");
        }
        while(node.next!=null){
            System.out.print(node.next.val+" ");
            node=node.next;
        }
    }
}