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#include <bits/stdc++.h>


using namespace std;


bool check(int total, int n, vector <int> &a) {
    int pref = 0;
    for (int i = 0; i < n; i++) {
        int x = 0;
        while (true) {
            long long maxMeet = (
                (long long) pref * x * (total - pref - x) +
                (long long) pref * x * (x - 1) / 2 +
                (long long) (total - pref - x) * x * (x - 1) / 2 +
                (long long) x * (x - 1) * (x - 2) / 6
            );

            if (maxMeet >= a[i]) {
                break;
            }

            x++;
        }

        pref += x;
        if (pref > total) {
            return false;
        }
    }

    return true;
}

int solve(int n, vector <int> &a) {
    const int MX = 1e6;

    int l = 0, r = MX;
    while (r - l > 1) {
        int mid = (l + r) / 2;
        if (check(mid, n, a)) {
            r = mid;
        } else {
            l = mid;
        }
    }

    return r;
}

int main() {
    ios_base::sync_with_stdio(false);

    int t;
    cin >> t;

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

        vector <int> a(n);
        for (int &ai : a) {
            cin >> ai;
        }

        cout << solve(n, a) << '\n';
    }

    return 0;
}