BC,HDU 5719

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long LL;
int a[100005],b[100005];
const LL mod=998244353;
int main()
{
#ifdef LOCAL
    freopen("in.txt","r",stdin);
#endif // LOCAL
    int T;
    scanf("%d",&T);
    while(T--)
    {
        memset(t,0,sizeof(t));
        LL ans=1;
        int n;
        scanf("%d",&n);
        for(int i=0; i<n; i++)
        {
            scanf("%d",&a[i]);
            if(i&&a[i]>a[i-1])
                ans=0;
        }
        for(int i=0; i<n; i++)
        {
            scanf("%d",&b[i]);
            if(i&&b[i]<b[i-1])
                ans=0;
        }
        if(ans)
        for(int i=1; i<n; i++)
        {
            if(a[i]==a[i-1]&&b[i]==b[i-1])
            {
                if(b[i]-a[i]-i+1<=0)//這個值等於(a[i],b[i])區間的數值)
                {
                    ans=0;
                    break;
                }
                ans=(ans*(b[i]-a[i]-i+1))%mod;
            }
            else if(a[i]!=a[i-1]&&b[i]!=b[i-1])
            {
                ans=0;
                break;
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}

=_=太智障以至於想不到b[i]-a[i]-i+1….