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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 PB push_back
#define EB emplace_back
#define FI first
#define SE second
#define umap unordered_map
#define uset unordered_set
#define vi vector<int>
#define vvi vector<vi>
#define vll vector<ll>
#define vvll vector<vll>
#define vpii vector<pii>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ALL(X) (X).begin(),(X).end()
#ifndef DEBUG
#define endl (char)10
#endif
using namespace std;
using ll = long long;
using ld = long double;

template <class T>
istream& operator>> (istream& is, vector<T>& vec){
    FOR(i,0,vec.size()) is >> vec[i];
    return is;
}
template <class T>
ostream& operator<< (ostream& os, vector<T>& vec){
    for(auto& t : vec) os << t << " ";
    return os;
}
template<class T, class U>
ostream& operator<< (ostream& os, const pair<T, U>& p){
    os << p.FI << " " << p.SE;
    return os;
}
template<class T, class U>
istream& operator>> (istream& is, pair<T, U>& p){
    is >> p.FI >> p.SE;
    return is;
}

vll npo3, npo2;

bool can(vll& V, ll t) {
    ll p = 0;
    // formula = (k po 3) + (k po 2) (t - k) + p k (t - p - k)
    auto bimbda = [&p, t, &npo3, &npo2](int x){ return npo3[x] + npo2[x] * (t - x) + p * x * (t - p - x); };
    FOR(i,0,V.size() - 1) {
        ll b = 0, e = min(t - p + 1, (ll) npo3.size());
        int bimbdab = -1;
        while(b < e) {
            int k = (b + e) / 2;
            //cout << p << " " << t << "; " << k << " -> " << bimbda(k) << endl;
            if (bimbda(k) < V[i]) b = k + 1;
            else e = k;
        }
        if (bimbda(b) < V[i]) return false;
        //cout << p << " " << t << "; " << i << "; stwierdzam " << b << endl;
        p += b;
        /*
        int k = ranges::lower_bound(
            ranges::iota_view{0, t - p + 1} | views::transform(bimbda),
            (int) V[i]
        );
        if(bimbda(k) < V[i]) return false;
        p += k;
        */
    }
    return t - p >= npo3.size() || bimbda(t - p) >= V.back();
}

void st() {
    int n;
    cin >> n;
    vll V(n);
    cin >> V;
    ll b = 0, e = (npo3.size() - 1) * n + 1;
    while(b < e) {
        ll t = (b + e) / 2;
        if(!can(V, t)) b = t + 1;
        else e = t;
    }
    cout << b << endl;
}

int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    FOR(i,0,1000){
        ll v = i * (i - 1) * (i - 2) / 6;
        ll v2 = i * (i - 1) / 2;
        npo3.PB(v);
        npo2.PB(v2);
        if (v > 1100000) break;
    }

    int t;
    cin >> t;
    FOR(i,0,t){
        if (t < 50){
            cerr << "-------------------" << endl;
        }
        //cout << "Case #" << i + 1 <<": ";
        st();
    }
}