#include <iostream>
#include <cstdio>
#include <cmath>
#include <string>
#include <cstring>
#include <algorithm>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <sstream>
#include <vector>
#define PI acos(-1.0)
const int  inf =  (1<<30) - 10;
using namespace std;
inline int get_int()
{
    int r=0;
    char c;
    while((c=getchar())!=' '&&c!='\n')
        r=r*10+c-'0';
    return r;
}
inline void out(int x)
{
    if(x>10)
    {
        out(x/10);
    }
    putchar(x % 10 + '0');
    putchar('\n');
}
/****************************************/

int b[100010],c[100010];
int main()
{
    __int64 m,zong;
    int t,n;
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        for(int i=0;i<n;i++)
            scanf("%d",&b[i]);
        for(int i=0;i<n;i++)
            scanf("%d",&c[i]);
        m=1;
        if(b[0]!=c[0]){
            printf("0\n");
            continue;
        }
        zong=0;
        for(int i=1;i<n;i++){
            if(b[i]>b[i-1]||c[i]<c[i-1]){
                m=-1;
                break;
            }
            if(b[i]!=b[i-1]&&c[i]!=c[i-1]){
                m=-1;
                break;
            }
            if(b[i]==b[i-1]&&c[i]==c[i-1]){
                if(zong<=0){
                    m=-1;break;
                }
                m*=zong;
                m%=998244353;
                zong--;
            }
            if(b[i]<b[i-1]){
                zong+=b[i-1]-b[i]-1;
            }
            if(c[i]>c[i-1]){
                zong+=c[i]-c[i-1]-1;
            }
        }
        if(m>0)
            printf("%I64d\n",m);
        else printf("0\n");
    }
    return 0;
}