$RT$,很简单的贪心模拟题,可是蒟蒻挑了2天了调不明白,求助555~

#include<stdio.h>
#define N 100010
#define mod 1000000007ll
long long ans,n,ma,mb,a[N],b[N];
void read()
{
	scanf("%lld",&n);
	scanf("%lld",&ma);
	for(long long i=1ll;i<=ma;++i)
	scanf("%lld",a+i);
	scanf("%lld",&mb);
	for(long long i=1ll;i<=mb;++i)
	scanf("%lld",b+i);	
}
long long max(long long x,long long y){return x>y?x:y;}
int main()
{
	read();
	long long res=1ll,ans1=0ll,ans2=0ll;
	for(long long i=ma;i>=1ll;--i)
	{
		ans1+=res*a[i]%mod,ans1%=mod;
		ans2+=res*b[i]%mod,ans2%=mod;
		res=res*max(a[i]+1ll,max(b[i]+1ll,2ll))%mod;
	}
	printf("%lld",(ans1-ans2+mod)%mod);
	return 0;	
}