#include <iostream>
#include <cmath>
using namespace std;
 
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int T;
    cin >> T;
    while(T--){
        int N;
        cin >> N;
        long long S = 0;
        for (int i = 0; i < N; i++){
            long long x;
            cin >> x;
            S += x;
        }
        // We want the maximum integer k such that k*(k-1)/2 <= S.
        // Solve k^2 - k - 2S <= 0.
        // The positive root is k = (1 + sqrt(1+8S)) / 2.
        long double disc = sqrt((long double)(1 + 8 * S));
        long long k = floor((1 + disc) / 2);
        
        // Adjust if necessary:
        while(k * (k - 1LL) / 2 > S) k--;
        while((k + 1LL) * k / 2 <= S) k++;
        
        cout << k << "\n";
    }
    return 0;
}