#include<bits/stdc++.h>
using namespace std;
int T,a[100005],b[100005];
int win[10],lost[10];
int main()
{
	cin>>T;
	win[1]=3;
	win[2]=1;
	win[3]=2;
	//win[i]能赢i 
	lost[3]=1;
	lost[1]=2;
	lost[2]=3;
	//lost[i]能输i 
	while(T--)
	{
		int n,x=0;
		memset(a,0,sizeof(a));
		memset(b,0,sizeof(b));
		cin>>n;
		for(int i=1;i<=2*n;i++)
		{
			cin>>a[i];
		}
		for(int i=1;i<=2*n;i++)
		{
			cin>>b[i];
		}
		// 
		cout<<2*n<<endl;
		for(int i=1;i<=n;i++)
		{
			cout<<win[b[i]]<<" ";
		}
		for(int i=n+1;i<=2*n;i++)
		{
			cout<<a[i]<<" ";
		}
		cout<<endl;
		for(int i=1;i<=n;i++)
		{
			cout<<b[i]<<" ";
		}
		for(int i=n+1;i<=2*n;i++)
		{
			cout<<lost[a[i]]<<" ";
		}
		cout<<endl;
		//
	}
    return 0;
}