1675b.cpp

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

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

        vector<int> a(n);
        for(int i = 0;i < n;i++)cin >> a[i];

        int ans = 0;
        bool poss = true;

        for(int i = n-2;i>=0;i--){
            while(a[i] >= a[i+1]){
                if(a[i] == 0){
                    poss = false;
                    break;
                }
                a[i] /= 2;
                ans++;
            }

            if(!poss) break;
        }

        if(poss){
            cout << ans << "\n";
        }else{
            cout << -1 << "\n";
        }
    }
    return 0;
}