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#include <bits/stdc++.h>
using namespace std;
#define FOR(i,l,r) for(int i = (l); i <= (r); i++)
#define FORD(i,l,r) for(int i = (l); i >= (r); i--)
using num = double;
using ind = long long;
bool try_solve(vector<int>& v, ind k){
    ind prev=0;
    ind future=k;
    for(ind x : v){
        if((k)*(k-1)*(k-2)/6 - prev*(prev-1)*future/2 - prev*(prev-1)*(prev-2)/6 < x){
            return false;
        }
        ind start = 1;
        ind end = min(250'000ll,future);
        while(start < end){
            ind center = (start+end)/2;
            if(prev*(center)*(future-center) + center*(center-1)*(prev+future-center)/2 +(center)*(center-1)*(center-2)/6 >= x){
                end = center;
            }else{
                start = center+1;
            }
        }
        prev += start;
        future -= start;
    }
    return true;
}
void solve(){
    int n;
    cin >> n;
    vector<int> v;
    FOR(i,1,n){
        int a;
        cin >> a;
        if(a > 0){
            v.push_back(a);
        }
    }
    if(v.size()==0){
        cout << 0 << '\n';
        return;
    }
    ind start = 1;
    ind end = 250'000;
    while(start < end){
        ind center = (start+end)/2;
        if(try_solve(v, center)){
            end = center;
        }else{
            start = center+1;
        }
    }
    cout << start << '\n';
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t;
    cin >> t;
    while(t--){
        solve();
    }
}