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#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=(a);i<(n);i++)
#define per(i,a,n) for (int i=(n)-1;i>=(a);i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> BI;
typedef long long ll;
typedef pair<int,int> PII;
typedef long double db;
mt19937 mrand(1111); 
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=200100;
int _,n,a[N];
void solve() {
	scanf("%d",&n);
	rep(i,1,n+1) scanf("%d",&a[i]);
	int s=0;
	rep(i,1,n+1) {
		int t=0;
		while (s*t*(t-1)/2+t*(t-1)*(t-2)/6<a[i]) t++;
		s+=t;
	}
	int l=-1,r=s;
	auto check=[&](ll x) {
		ll s=0;
		rep(i,1,n+1) {
			ll t=0;
			while (s+t<=x&&
				s*t*(t-1)/2+t*(t-1)*(t-2)/6+t*(t-1)/2*(x-s-t)+s*t*(x-s-t)<a[i]) t++;
			s+=t;
			if (s>x) return false;
		}
		return true;
	};
	while (l+1<r) {
		int md=(l+r)>>1;
		if (check(md)) r=md; else l=md;
	}
	printf("%d\n",r);
}
int main() {
	for (scanf("%d",&_);_;_--) {
		solve();
	}
}