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#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;

const int N = 2e5 + 5;
const int LIM = 1<<20;

int A[N];

ll Check2(ll used, ll left, ll cnt)
{
    ll sol = used * cnt * left;
    sol += ((cnt * (cnt - 1)) / 2) * (used + left);
    sol += (cnt * (cnt - 1) * (cnt - 2)) / 6;
    return sol;
}

int BinSearch(int used, int K, ll need)
{
    int beg = -1, end = K, mid;

    while(end - beg > 1) {
        mid = (beg + end) / 2;

        if(Check2(used, K - mid, mid) >= need)
            end = mid;
        else
            beg = mid;
    }
    return end;
}

bool Check(int K, int n)
{
    int used = 0;
    for(int i = 0; i < n; i++) {
        int help = BinSearch(used, K, A[i]);

        if(Check2(used, K - help, help) < A[i])
            return false;
        used += help;
        K -= help;
    }
    return true;
}

int Solve(int n)
{
    int beg = 0, end = LIM, mid;

    while(end - beg > 1) {
        mid = (beg + end) / 2;

        if(Check(mid, n))
            end = mid;
        else
            beg = mid;
    }
    return end;
}

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

    int t, n;
    cin >> t;

    while(t --> 0) {
        cin >> n;

        for(int i = 0; i < n; i++)
            cin >> A[i];

        cout << Solve(n) << "\n";
    }
    return 0;
}