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#include <algorithm>
#include <bitset>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
#include <cmath>

using namespace std;

#define PB push_back
#define MP make_pair
#define F first
#define S second
#define ALL(x) (x).begin(),(x).end()
#define SIZE(x) (int)(x).size()
#define CLEAR(tab) memset(tab, 0, sizeof(tab))
#define REP(x, n) for(int x = 0; x < (n); x++)
#define FOR(x, b, e) for(int x = (b); x <= (e); x++)
#define FORD(x, b, e) for(int x = (b); x >= (e); x--)
#define VAR(v, n) __typeof(n) v = (n)
#define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define DEBUG(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__)

typedef long long int LL;
typedef pair<int,int> PII;
typedef vector<int> VI;

const int MXN = 200010;
const int C = 262144;
const int INF = 1000000001;
const int MOD = 1000000007;

int n;
int a[MXN];
int b[MXN];
LL sum;

LL calc(LL x, LL prev, LL total, int i) {
    if(i == n)
        return (x * (x - 1) * (x - 2)) / 6 + (x * (x - 1) / 2) * (total - x);
	return (x * (x - 1) * (x - 2)) / 6 + (x * (x - 1) / 2) * (total - x) + x * prev * (total - prev - x);
}

bool check(LL k) {
	if(k * (k - 1) * (k - 2) / 6 < sum)
		return 0;
	LL total = 0;
	FOR(i, 1, n) {
        if(a[i] == 0)
            continue;
		LL L = 0, R = k - total;
		LL res = -1;
		while(L <= R) {
			LL S = (L + R) / 2;
			if(calc(S, total, k, i) >= a[i]) {
				res = S;
				R = S - 1;
			}
			else
				L = S + 1;
		}
		if(res == -1 || res > k - total)
			return 0;
		total += res;
	}
	return 1;
}

void test() {
	scanf("%d", &n);
	FOR(i, 1, n) {
		scanf("%d", &a[i]);
		sum += a[i];
	}
	LL L = 3, R = 3;
	while(!check(R))
		R *= 2;
	LL res = R;
	while(L <= R) {
		LL S = (L + R) / 2;
		if(check(S) ) {
			res = min(res, S);
			R = S - 1;
		}
		else
			L = S + 1;
	}
	printf("%lld\n", res);
	sum = 0;
}

int main() {
	int te = 1;
	scanf("%d", &te);
	while(te--)
		test();
	return 0;
}