#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <string.h>
#include <string>
#include <vector>
using namespace std;

const int MOD = 998244353;
const int MAXN = 100010;
int B[MAXN];
int C[MAXN];
int A[MAXN];
bool used[MAXN];

int main() {
    int T;
    scanf("%d", &T);
    while(T--) {
        int n ;
        scanf("%d",&n);
        B[0] = 100000000;
        C[0] = -1;
        for(int i = 1;i <= n;i++)scanf("%d",&B[i]);
        for(int i = 1;i <= n;i++)scanf("%d",&C[i]);
        bool flag = true;
        for(int i = 2;i <= n;i++) {
            if (B[i] > B[i-1])
                flag = false;
            if(C[i] < C[i-1])
                flag = false;
        }
        memset(used,false,sizeof(used));
        memset(A,-1,sizeof(A));
        long long ans = 1;
        for(int i = 1;i <= n;i++) {
            if(!flag)break;
            if (B[i] > C[i]){
                flag = false;
                break;
            }
            if (B[i] < B[i-1] ) {
                A[i] = B[i];
            }
            if(C[i] > C[i-1]) {
                if (A[i] != -1 && A[i] != C[i]) {
                    flag = false;
                }
                A[i] = C[i];
            }
            if (A[i] != -1) {
                if (B[i] > A[i])flag = false;
                if (C[i] < A[i]) flag = false;
                if (used[A[i]]) flag = false;
                used[A[i]] = true;
            }
            if (!flag)break;
            if (A[i] == -1) {
                ans = ans * (C[i] - B[i] + 1 - (i-1))%MOD;
            }
        }
        if (!flag) puts("0");
        else {
            printf("%d\n",(int)ans);
        }

    }
    return 0;
}