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

#define FOR(i, l, r) for(int i = (l); i <= (r); ++i)
#define REP(i, n) FOR(i, 0, (n) - 1)
#define ssize(x) int(x.size())
#ifdef DEBUG
auto &operator << (auto &o, pair<auto, auto> p) {
	return o << "(" << p.first << ", " << p.second << ")";
}
auto operator << (auto &o, auto x) -> decltype(x.end(), o) {
	o << "{"; int i = 0;
	for (auto e : x) o << ","+!i++ << e;
	return o << "}";
}
#define debug(X...) cerr << "["#X"]: ", [](auto ...$) {((cerr << $ << "; "), ...) << endl;}(X)
#else
#define debug(...) {}
#endif

#ifdef DEBUG
constexpr int INF = 10;
#else
constexpr int INF = int(1e9);
#endif

int minimize(long long n, long long pref, long long bound) {
	auto f = [&](long long x) {
		if (pref + x >= n) return -1LL;
		return 
			(x * (x - 1) * (x - 2) / 6) +
			(x * (x - 1) / 2) * (n - x) +
			pref * x * (n - pref - x);	
	};

	int left = 0, right = min(200LL, n - pref);
	int answer = -1;
	while (left <= right) {
		int mid = (left + right) / 2;
		debug(left, right, mid, f(mid));
		if (f(mid) >= bound) {
			answer = mid;
			right = mid - 1;
		} else {
			left = mid + 1;
		}
	}

	return answer;
}

bool check(int total_players, const vector<int> &a) {
	debug(total_players);
	int n = ssize(a);
	vector<int> x(n);

	int pref = 0;
	REP (i, n) {
		x[i]  = minimize(total_players, pref, a[i]);
		if (x[i] == -1) return false;
		pref += x[i];
	}

	return pref <= total_players;
}

void solve() {
	int n; cin >> n;
	vector<int> a(n);
	REP (i, n) cin >> a[i];

	int left = 1, right = INF;
	int answer = -1;
	while (left <= right) {
		int mid = (left + right) / 2;
		if (check(mid, a)) {
			right = mid - 1;
			answer = mid;
		} else {
			left = mid + 1;
		}
	}

	assert(answer != -1);
	cout << answer << '\n';
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	int t; cin >> t;
	while (t--) 
		solve();
}