#include <bits/stdc++.h>
using namespace std;
#define int              long long int
#define double           long double
#define print(a)         for(auto x : a) cout << x << " "; cout << endl


const int M = 1000000007;
const int N = 3e5+9;
const int INF = 2e9+1;
const int LINF = 2000000000000000001;

inline int power(int a, int b, int mod=M) {
    int x = 1;
    a %= mod;
    while (b) {
        if (b & 1) x = (x * a) % mod; 
        a = (a * a) % mod;
        b >>= 1;
    }
    return x;
}


//_ ***************************** START Below *******************************




vector<int> a;

bool isPossible(int n, int mid){

    vector<int> b(a);

    for(int i=n-1; i>=2; i--){

        int dif = b[i] - mid;
        int d = min(a[i], dif)/3;

        if(dif<0) return false;

        b[i-2] += 2*d;
        b[i-1] += d;
        b[i] -= 3*d;
    }


    for(int i=0; i<n; i++){
        if(b[i] < mid) return false;
    }
    return true;
}

int consistency(int n){

    int s = 0, e = INF;

    while(s<e){
        int mid = s + (e-s+1)/2;
        if(isPossible(n, mid)){
            s = mid;
        }
        else{
            e = mid-1;
        }
    }

    return s;
}















int practice(int n){


    return 0;
}





void solve() {
    
    int n;
    cin>> n;
    
    a.resize(n);
    for(int i=0; i<n; i++) cin >> a[i];
    
    cout << consistency(n) << endl;


}





int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}