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// clang-format off
#include<bits/stdc++.h>
using namespace std;
using LL=long long;
#define FOR(i,l,r) for(auto i=(l);i<=(r);++i)
#define REP(i,n) FOR(i,0,(n)-1)
#define ssize(x) int(x.size())
template<class A,class B>auto&operator<<(ostream&o,pair<A,B>p){return o<<"("<<p.first<<", "<<p.second<<")";}
template<class T>auto operator<<(ostream&o,T x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<(", ")+2*!i++<<e;return o<<"}";}
#ifdef DEBUG
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<"\n";}(X)
#else
#define debug(...) {}
#endif
// clang-format on

const int max_per_building = 185;
int ntests, N;
vector<int> seq;

// Is it possible with at most M guys?
bool
check(int M)
{
    int sofar_atleast = 0;
    auto func         = [&M, &sofar_atleast](LL b) -> LL
    {
        LL res = b * sofar_atleast * (M - b - sofar_atleast);
        if (b >= 2)
            res += (b * (b - 1) * (b - 2)) / 6 + ((b * (b - 1)) / 2) * (M - b);
        return res;
    };

    REP (i, N) {
        LL b = 0;
        while (b + sofar_atleast <= M && func(b) < seq[i]) ++b;
        sofar_atleast += b;
        if (sofar_atleast > M) return false;
    }
    debug(M, true);
    return true;
}

int
solve()
{
    cin >> N;
    seq.resize(N);
    for (auto& x : seq) cin >> x;

    int l = 3, r = max_per_building * N;
    while (l < r) {
        int mid = (l + r) >> 1;
        if (check(mid))
            r = mid;
        else
            l = mid + 1;
    }
    return l;
}

int
main()
{
    cin.tie(0)->sync_with_stdio(0);
    cin >> ntests;
    while (ntests--) cout << solve() << "\n";
    return 0;
}