题解 | #学英语#

import java.util.*;


public class Main{
    
    
    public static void main(String[] arg){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            
            String[] strs = sc.nextLine().split(" ");
            int N = Integer.parseInt(strs[0]);
            int[] arr = new int[N*2];
            for(int i= 1;i<N*2;i++){
                arr[i] = Integer.parseInt(strs[i]);
            }
            int del = Integer.parseInt(strs[2*N]);
            
            Node tou = new Node(arr[1]);
            for(int i= 2;i<N*2;i=i+2){
                zhao(tou,arr[i],arr[i+1]);
            }
//             Node head = tou;
//             while(head!=null){
//                 System.out.print(head.val+" ");
//                 head=head.next;
//             }
            //删除
            shan(tou,del);
            Node head = tou;
            while(head!=null){
                System.out.print(head.val+" ");
                head=head.next;
            }
            
        }
    }
    public static void zhao(Node tou,int x,int y){
        Node head = tou;
        while(head!=null){
            if(head.val==y){
                Node tem = new Node(x);
                Node hou = head.next;
                head.next = tem;
                tem.next = hou;
                break;
            }else{
                head=head.next;
            }
        }
    }
    public static Node shan(Node tou,int val){
        Node head = tou;
        if(head==null){
            return null;
        }
        if(head.next==null){
            if(head.val!=val){
                return null;
            }else{
                return null;
            }
        }
        if(head.val==val){
            tou=head.next;
            return tou;
        }
        while(head.next!=null){
            if(head.next.val==val){
                head.next = head.next.next;
                break;
            }else{
                head=head.next;
            }
        }
        return tou;
    }
     
}
class Node{
         int val;
         Node next;
         public Node(int val){
             this.val = val;
         }
}