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#include <bits/stdc++.h>

using namespace std;

const int N = 200004;
int A[N];
int U[N]; // uzyte

int ile_min_osob(int wszystkie, int uzyte, int bound) {
    int L = 0, R = wszystkie - uzyte + 1;
    while(L < R) {
        int M = (L+R)/2;
        long long mecze = (long long)M*(M-1)*(M-2)/6 + (long long)M*(M-1)/2*(wszystkie-M) + (long long)(wszystkie-M-uzyte)*M*uzyte;
        if(mecze < bound) L = M+1;
        else R = M;
    }

    if(L == wszystkie - uzyte + 1) return -1;
    return L;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int t;
    cin >> t;

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

        for(int i = 1; i <= n; i++) cin >> A[i];

        int a = 1, b = 1000000;
        while(a < b) {
            int m = (a+b)/2;
            U[n+1] = 0;
            bool czy = true;
            for(int i = n; i >= 1; i--) {
                int obecne = ile_min_osob(m, U[i+1], A[i]);
                if(obecne == -1) {
                    czy = false;
                    break;
                }
                U[i] = obecne + U[i+1];
            }

            if(!czy) a = m+1;
            else b = m;
        }

        cout << a << "\n";
    }   


    return 0;
}