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#include <bits/stdc++.h>
using namespace std;

using ll = int64_t;

using i128 = __int128_t;

void solve(){
	int N;
	cin >> N;
	vector<ll> A(N);
	for(int i = 0; i < N; i++) cin >> A[i];
	ll s = 0;
	ll e = 1e9;
	while(s + 1 < e){
		ll mid = (s+e) / 2;
		ll tot = mid;

		bool ok = true;
		ll prv = 0;
		ll nleft = tot;
		for(int i = 0; i < N; i++){
			ll s1 = -1;
			ll e1 = nleft + 1;
			auto ncr3 = [&](i128 c) -> i128 {
				return c * (c-1) * (c-2) / 6;
			};
			auto ncr2 = [&](i128 c) -> i128 {
				return c * (c-1) / 2;
			};
			while(s1 + 1 < e1){
				ll m1 = (s1 + e1) / 2;
				i128 x = m1;
				i128 good = ncr3(x) + ncr2(x) * (tot - x) + x * prv * (tot - x - prv);
				(good >= A[i] ? e1 : s1) = m1;
			}
			if(e1 > nleft){
				ok = false;
				break;
			}
			prv += e1;
			nleft -= e1;
		}
		(ok ? e : s) = mid;
	}
	cout << e << '\n';
}

int main(){
	ios_base::sync_with_stdio(false), cin.tie(nullptr);
	int T;
	cin >> T;
	while(T--) solve();
}