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#include<bits/stdc++.h>

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define VAR(v, i) __typeof(i) v=(i)
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)


#define VI vector<int>
#define PII pair<int,int>
#define st first
#define nd second
#define mp make_pair
#define pb push_back
#define lint long long int


#define debug(x) {cerr <<#x <<" = " <<x <<endl; }
#define debug2(x,y) {cerr <<#x <<" = " <<x << ", "<<#y<<" = "<< y <<endl; }
#define debug3(x,y,z) {cerr <<#x <<" = " <<x << ", "<<#y<<" = "<< y << ", " << #z << " = " << z <<endl; }
#define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<endl; }}
#define debugt(t,n) {{cerr <<#t <<" = "; FOR(it,0,(n)) cerr <<t[it] <<", "; cerr <<endl; }}


#define make( x) int (x); scanf("%d",&(x));
#define make2( x, y) int (x), (y); scanf("%d%d",&(x),&(y));
#define make3(x, y, z) int (x), (y), (z); scanf("%d%d%d",&(x),&(y),&(z));
#define make4(x, y, z, t) int (x), (y), (z), (t); scanf("%d%d%d%d",&(x),&(y),&(z),&(t));
#define IOS ios_base::sync_with_stdio(0)
#define HEAP priority_queue


#define read( x) scanf("%d",&(x));
#define read2( x, y) scanf("%d%d",&(x),&(y));
#define read3(x, y, z) scanf("%d%d%d",&(x),&(y),&(z));
#define read4(x, y, z, t) scanf("%d%d%d%d",&(x),&(y),&(z),&(t));


using namespace std;

int N;
int t[200005];

lint po3(int n) {
	if (n > 200) return 1e6;
	lint x = n * 1LL * (n -1) * 1LL * (n-2);
	return x/6;
}

lint po2(int n) { 
	if (n > 1500) return 1e6; 
	return (n * 1LL * (n-1)) / 2;
}

bool ok(int pos, int ja, int S, int sofar) {
	if (ja != 0) {
		if (sofar * 1LL * (S-sofar-ja) > t[pos]/ja) return true;
	}
	return (po3(ja) + po2(ja)*1LL*(S-ja) + sofar * 1LL * ja * 1LL * (S-sofar - ja)) >= t[pos]; 
}

bool check(int S) {
	int sofar = 0;
	for (int i = 0; i < N; i++) {
		int ja = S - sofar;
		if (!ok(i,ja,S,sofar)) return false;
		int lewo = 0; int prawo = ja;
		while (prawo - lewo > 1) {
			int mid = (prawo + lewo) / 2;
			if (ok(i,mid,S,sofar)) prawo = mid;
			else lewo = mid;
		}
		if (ok(i,lewo,S,sofar)) ja = lewo;
		else ja = lewo + 1;
		sofar += ja;
		if (sofar > S) return false;
	}
	return true;
}

void solve() {
	read(N);
	FOR(i,0,N) {
		make(a);
		t[i] = a;
	}
	int lewo = 0; int prawo = 183*N;
	while (prawo - lewo > 1) {
		int mid = (prawo + lewo) / 2;
		if (check(mid)) prawo = mid;
		else lewo = mid;
	}
	if (check(lewo)) printf("%d\n", lewo);
	printf("%d\n", prawo);
}


int main() {
	make(z);
	while (z--) {
		solve();
	}
}