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#include <cstdio>
#include <vector>
#define FOR(i,a,b) for(int i=(int)(a); i<(int)(b); ++i)
#define ulli unsigned long long int
using namespace std;

int t, n, a;
vector<int> A;

bool try_result(int N) {
    int used = 1;
    FOR(i,0,A.size()) {
        ulli max_games = 0;
        while (max_games < (ulli)A[i] && used <= N && (N - used >= A.size() - i)) {
            max_games += (ulli)(used) * (ulli)(N - used - 1);
            ++used;
        }
        if (max_games < (ulli)(A[i])) return false;
    }
    return true;
}

int main() {
    scanf("%d", &t);
    while (t--) {

        // Read input
        A.clear();
        scanf("%d", &n);
        FOR(i,0,n) {
            scanf("%d", &a);
            if (a > 0) A.push_back(a);
        }

        // Binsearch
        int L = 2, R = 1000005;
        int result = R;
        while (L<=R) {
            int M = (L+R)/2;
            if (!try_result(M)) L = M+1;
            else {
                result = M;
                R = M-1;
            }
        }

        printf("%d\n", result);
    }
}