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#include <vector>
#include <cstdio>
#include <stack>
#include <algorithm>
#include <queue>
#include <map>
#include <cmath>
#include <unordered_set>
#include <unordered_map>
#include <set>
#include <cstring>
#include <bitset>
#include <iostream>
#include <queue>
#include <iomanip>
#include <complex>

using namespace std;

#define ALL(x) x.begin(), x.end()
#define UNIQUE(c) (c).resize(unique(ALL(c)) - (c).begin())
#define FOR(i, a, b) for(int i =(a); i <=(b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define RED(i, n) FORD(i, n, 1)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define REP(i, n) for(int i = 0;i <(n); ++i)
#define REPD(i, n) FORD(i, n-1,0)

#define printA(a, L, R) FOR(i,L,R) cout << a[i] << (i==R?'\n':' ')
#define printV(a) printA(a,0,a.size()-1)
#define PRESENT(c, x) ((c).find(x) != (c).end())
#define CPRESENT(c, x) (find(ALL(c),x) != (c).end())
#define bit(x, i) (x&(1<<i))
#define lowbit(x) ((x)&((x)^((x)-1)))

const int fx[4][2] = {
    {0, 1},
    {1, 0},
    {0, -1},
    {-1, 0}
};
const int fxx[8][2] = {
    {0, 1},
    {0, -1},
    {1, 0},
    {-1, 0},
    {1, 1},
    {1, -1},
    {-1, 1},
    {-1, -1}
};
const int sk[8][2] = {
    {2, 1},
    {2, -1},
    {-2, -1},
    {-2, 1},
    {1, 2},
    {-1, 2},
    {1, -2},
    {-1, -2}
};

const int maxn = 200012;
long long mod = 998244353ll;
const long long inf = 10000000000012ll;

const long long mam = 200;
long long n, l, r, mid, a[maxn];

void solve() {
    cin >> n;
    REP(i, n) cin >> a[i];
    l = 3; r = n * mam;
    while (l <= r) {
        mid = (l + r) / 2;
        bool ok = true;
        long long akt = mid, lewo = 0ll;
        REP(i, n) {
            long long l2 = 0, r2 = min(mam, akt);
            while (l2 <= r2) {
                long long mid2 = (l2 + r2) / 2;
                long long res = mid2 * (mid2 - 1ll) * (mid2 - 2ll) / 6ll;
                long long prawo = (i < n - 1) ? (akt - mid2) : 0ll;
                res += (lewo + prawo) * mid2 * (mid2 - 1ll) / 2ll;
                res += lewo * prawo * mid2;
                if (res < a[i])l2 = mid2 + 1ll;
                else r2 = mid2 - 1ll;
            }
            if (l2 > akt) {
                ok = false;
                break;
            }
            akt -= l2;
            lewo += l2;
        }
        if (ok) r = mid - 1;
        else l = mid + 1;
    }
    cout<<l<<"\n";
}

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

    int tt = 1;
    cin >> tt;
    while (tt--) {
        solve();
    }
    return 0;
}