【超时】1-7 两个有序链表序列的交集 (20 分)

                 本文链接：[https://blog.csdn.net/shiliang97/article/details/100096326](https://blog.csdn.net/shiliang97/article/details/100096326) 

1 2 5 -1
2 4 5 8 10 -1

2 5

#include<iostream>
#include<map>
using namespace std;
map<int,int>a;
int main(){
	int n=0;
	while(n!=-1){
		cin>>n;
		a[n]=10;
	}a[-1]=0;
	int flag=0;
	while(1){
		cin>>n;
		if(n==-1){
			if(flag==0){
				cout<<"NULL";
			}
			return 0;
		}
		if(a[n]==10){
			if(flag){
				cout<<" ";
			}flag=1;
			cout<<n;
            a[n]=0;	
		}		
	}
	return 0;
}