#include <bits/stdc++.h>
#define ll long long
#define pll pair<ll,ll>
#define f first
#define s second
using namespace std;
const ll N=1e6+10;
ll t,n,a[N],b[N],l,r,mid,ans;
deque<ll> q;
bool check(ll mid){
	q.clear();
	ll k=1,coin=0,bef=b[1];//coin是剩余，lef是当前位置的天数
	for(ll i=1;i<=n;i++){
		while(!q.empty()&&a[q.back()]<a[i]){
			q.pop_back();
		}
		q.push_back(i);
		ll need=mid;//需要花的钱数
		if(need<=coin){
			coin-=need;
			need=0;
		}else{
			need-=coin;
			coin=0;
		}
		while(need){
			if(bef*a[q.front()]>=need){
				ll cost=ceil(need*1.0/a[q.front()]);//数学公式
				bef-=cost;
				coin+=cost*a[q.front()]-need;
				need=0;
			}else{
				need-=bef*a[q.front()];
				k++;
				bef=b[k];
				if(q.front()<k){
					q.pop_front();
				}
				if(k>i){
					return 0;
				}
			}	
		}
	}
	return 1;
}
signed main(){
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>t;
	while(t--){
		cin>>n;
		for(ll i=1;i<=n;i++){
			cin>>a[i];
		}
		for(ll i=1;i<=n;i++){
			cin>>b[i];
		}
		l=0,r=1e15;
		while(l<=r){
			mid=l+r>>1;
			if(check(mid)){
				l=mid+1;
				ans=mid;
			}else{
				r=mid-1;
			}
		}
		cout<<ans<<'\n';
	}
	return 0;
}

麻烦大佬们优化一下!