#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define mod 998244353
#define N 200005
using namespace std;
typedef long long ll;
ll cas,n,i,pp,last,now,Mi,mx,ans,premi,premx,j;
ll mi[N],ni[N],a[N],b[N],flag[N],ok[N];
ll C(ll x,ll y)
{
    if (y==0||x==y)return 1;
    return mi[x]*ni[y]%mod*ni[x-y]%mod;
}
int main()
{
    mi[0]=ni[0]=ni[1]=1;
    for (i=1;i<N;i++)mi[i]=mi[i-1]*i%mod;
    for (i=2;i<N;i++)ni[i]=(mod-mod/i)*ni[mod%i]%mod;
    for (i=2;i<N;i++)ni[i]=ni[i]*ni[i-1]%mod;
    scanf("%I64d",&cas);
    while (cas--)
    {
        scanf("%I64d",&n);
        for (i=1;i<=n;i++)scanf("%I64d",&a[i]);
        for (i=1;i<=n;i++)scanf("%I64d",&b[i]);
        pp=0;
        for (i=1;i<=n;i++)
            if (a[i]>b[i])
            {
                pp=1;
                break;
            }
        for (i=2;i<=n;i++)
            if (a[i-1]<a[i])
            {
                pp=1;
                break;
            }
        for (i=2;i<=n;i++)
            if (b[i-1]>b[i])
            {
                pp=1;
                break;
            }
        //printf("pp %I64d\n",pp);
        if (pp){puts("0");continue;}
        for (i=1;i<=n;i++)flag[i]=0,ok[i]=0;
        for (i=1;i<=n;i++)
            if (a[i]!=a[i-1])
            {
                flag[a[i]]=1;
                ok[i]=a[i];
            }
        for (i=1;i<=n;i++)
            if (b[i]!=b[i-1])
            {
                flag[b[i]]=1;
                ok[i]=b[i];
            }
        //for (i=1;i<=n;i++)printf("%I64d ",ok[i]);puts("");
        now=0;i=1;Mi=n+10;mx=0;last=0;
        premi=n+10;premx=0;ans=1;
        while (i<=n)
        {
            if (ok[i])
            {
                Mi=min(Mi,ok[i]);
                mx=max(mx,ok[i]);
                last=i;i++;
                continue;
            }
            if (premx==0)
            {
                for (j=Mi;j<=mx;j++)
                    if (!flag[j])now++;
                premx=mx;premi=Mi;
            }else
            {
                for (j=premx+1;j<=mx;j++)
                    if (!flag[j])now++;
                for (j=Mi;j<=premi-1;j++)
                    if (!flag[j])now++;
                premx=mx;premi=Mi;
            }
            //printf("%I64d %I64d %I64d\n",now,last,i);
            while (!ok[i] && i<=n)i++;
            ans=ans*C(now,i-last-1)%mod*mi[i-last-1]%mod;
            now-=i-last-1;
        }
        printf("%I64d\n",ans);
    }
}