/*
 *Copyright (c) Swadheen Islam Robi (SIR01)
 *Created on Tue Nov 05 2024 10:10:11 PM
 */
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define pie 2*(acos(0.0))
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define pb push_back
#define endl "\n"
#define lcm(a,b) (a*b)/(__gcd<ll>(a,b))
#define mod 1000000007
#define srt(v) sort(v.begin(),v.end())
#define rsrt(v) sort(v.rbegin(),v.rend())
#define ALLAHU_AKBAR ios::sync_with_stdio(false); cin.tie(nullptr);

void sir()
{
    // int y
    ll n; cin>>n;
    vector<ll>a(n);
    ll sum = 0;
    for(ll i=0; i<n; i++) cin>>a[i], sum+=a[i];
    //cout<<sum<<endl;
    // srt(a);
    // ll k =0;
    // ll ans;
    // for(ll i=0; i<n; i++)
    // {
    //     if(a[i]==k){
    //         k++;
    //     }
    //     else{
    
    //     ll chk = a[i];
    //     ans = k;
    //         while(1)
    //         {
    //             i++;
    //             chk += a[i];
    //             if(chk>=ans) ans = chk;
    //             else break;

    //         }
    //     }
    // }
    ll ans;
    ll lo = 1, hi = 1e9 + 7;
    while(lo<=hi)
    {
        ll mid = lo + (hi-lo)/2;
        ll need = mid*(mid+1)/2;
        if(need>sum){
            ans = mid;
            hi = mid -1;
        }
        else lo = mid + 1;;
    }
    cout<<ans<<endl;
}

int main() {
    ALLAHU_AKBAR

    ll t = 1;
    cin>>t;
    while(t--)
    {
        sir();
    }
    return 0;
}