#include <cstdio>
#include <iostream>
#include <cstring>
#include <string>
#include <algorithm>
#define ll long long
#define mst(a,x) memset(a,x,sizeof(a))
#define For(i,n) for(int i=0; i<n; i++)
using namespace std;

const int N = 1e5 + 5;
const int MOD = 998244353;
int mn[N], mx[N], cnt, n;


int solve() {
    bool fail = 0;
    for(int i = 1; i <= n; i++) {
        scanf("%d", mn + i);
        if(i > 1 && mn[i] > mn[i - 1]) fail = 1;
    }
    for(int i = 1; i <= n; i++) {
        scanf("%d", mx + i);
        if(i > 1 && mx[i] < mx[i - 1]) fail = 1;
    }
    if(fail) return 0;

//    puts("not fail");
    int ans = 1;
    for(int i = 1; i <= n; i++) {
        if(mn[i] != mn[i - 1] && mx[i] != mx[i - 1] && mn[i] != mx[i]) return 0;
        if(mn[i] > mx[i]) return 0;
        if(mn[i] != mn[i - 1] || mx[i] != mx[i - 1]) continue;
        int cnt = mx[i] - mn[i] + 1 - (i - 1);
        ans = (ll)ans * cnt % MOD;
    }
    return ans;
}

int main() {
    int T;

    scanf("%d", &T);
    while(T--) {
        scanf("%d", &n);
        printf("%d\n", solve());

    }
    
    return 0;
}