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#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<pii> vpii;
typedef vector<string> vs;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef long double ld;
typedef unordered_map<int, int> umii;
typedef vector<pair<ll, ll>> vpll;
typedef tuple<int, int, int> tp;
typedef unsigned long long ull;
const ll mod = 1e9+696969;

inline ll b2(ll n)
{
    if(n < 2) return 0;
    return n*(n-1)/2;
}

inline ll b3(ll n)
{
    if(n < 3) return 0;
    return n*(n-1)*(n-2)/6;
}

inline ll f_nl(ll p, ll l, ll tot)
{
    ll t1 = b3(p);
    ll t2 = b2(p) * (tot - p);
    ll r = tot - l - p;
    ll t3 = p * l * r;
    return t1 + t2 + t3;
}

inline ll f_l(ll p, ll l)
{
    ll t1 = b3(p);
    ll t2 = b2(p) * l;
    return t1 + t2;
}

bool ok(ll tot, vll &v)
{
    int n = v.size();
    ll l = 0;
    for (int i = 0; i < n - 1; i++)
    {
        ll r = tot - l;
        if(f_nl(r, l, tot) < v[i]) return false;
        ll lo = 0, hi = r;
        while(lo < hi)
        {
            ll mid = lo + (hi - lo) / 2;
            if(f_nl(mid, l, tot) >= v[i])
                hi = mid;
            else
                lo = mid + 1;
        }
        ll c = lo;
        l += c;
        if(l > tot) return false;
    }
    ll p_l = tot - l;
    if(p_l < 0) return false;
    if(f_l(p_l, l) < v[n-1]) return false;
    return true;
}

void solve()
{
 
    int t;
    cin >> t;
    while(t--)
    {
        int n;
        cin >> n;
        vll v(n);
        ll s = 0;
        for (int i = 0; i < n; i++)
        {
            cin >> v[i];
            s += v[i];
        }
        ll lot = 3;
        {
            ll lo = 3, hi = max(3LL, 1LL);
            while(b3(hi) < s)
            {
                hi *= 2;
                if(hi > 10000000LL) break;
            }
            while(lo < hi)
            {
                ll mid = lo + (hi - lo) / 2;
                if(b3(mid) >= s)
                    hi = mid;
                else
                    lo = mid + 1;
            }
            lot = max(lot, lo);
        }
        ll hit = max(lot, 100LL);
        while(!ok(hit, v))
        {
            hit *= 2;
            if(hit > (ll)1e12) break;
        }
        ll ans = hit;
        ll l = lot, h = hit;
        while(l <= h)
        {
            ll mid = l + (h - l) / 2;
            if(ok(mid, v))
            {
                ans = mid;
                h = mid - 1;
            }
            else
            l = mid + 1;
            
        }
        cout << ans << "\n";
    }
  
}

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

    solve();
    return 0;
}