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#include <bits/stdc++.h>
using namespace std;

#define int long long

int tab[200007];
int n;

bool check(int L, int X, int R, int i) {
    __int128 m = (__int128)tab[i];
    __int128 l = (__int128)(L);
    __int128 x = (__int128)(X);
    __int128 r = (__int128)(R);
    // cout << "check " << l << " " << x << " " << r << " " << m << "\n";
    // cout << l * x * r + (x * (x - 1) * (l + r)) / 2 + (x * (x - 1) * (x - 2)) / 6 << "\n";
    return l * x * r + (x * (x - 1) * (l + r)) / 2 + (x * (x - 1) * (x - 2)) / 6 >= m;
}

bool enoughL(int w) {
    // cout << "enough " << w << "\n";
    int l = 0, r = w;
    for (int i = 0; i < n; i++) {
        if (tab[i] > 0) {
            if (r <= 0) return false;

            int p = 1, k = r;
            while (p < k) {
                int s = (p + k) / 2;
                if (!check(l, s, r - s, i)) {
                    p = s + 1;
                }
                else {
                    k = s;
                }
            }
            if (!check(l, p, r - p, i)) {
                return false;
            }
            // cout << "assign " << i << " " << p << "\n";
            l += p;
            r -= p;         
        }

    }
    return true;
}

bool enoughR(int w) {
    //cout << "enough " << w << "\n";
    int l = w, r = 0;
    for (int i = n - 1; i >= 0; i--) {
        if (tab[i] > 0) {
            if (l <= 0) return false;

            int p = 1, k = l;
            while (p < k) {
                int s = (p + k) / 2;
                if (!check(l, s, l - s, i)) {
                    p = s + 1;
                }
                else {
                    k = s;
                }
            }
            if (!check(l - p, p, r, i)) {
                return false;
            }
            //cout << "assign " << i << " " << p << "\n";
            l -= p;
            r += p;         
        }

    }
    return true;
}

signed main() {

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    int t;
    cin >> t;
    while (t > 0) {
        t--;
        cin >> n;

        int p = 0, k = 2;

        for (int i = 0; i < n; i++) {
            cin >> tab[i];
            k += tab[i];
        }

        
        while (p < k) {
            int s = (p + k) / 2;
            if (!enoughL(s)) {
                p = s + 1;
            }
            else {
                k = s;
            }
        }
        cout << p << "\n";
    }
}