#include <bits/stdc++.h>   using namespace std;   int t, n;   long long a[100005];   int get_bit(long long x) {     int ans = 0;     while (x) {       ans++;       x >>= 1;     }     return ans;   }   int main() {     int i, j;     scanf( %d , &t);     while (t--) {       scanf( %d , &n);       for (i = 1; i <= n; i++) scanf( %lld , &a[i]);       int ans = 0, last = a[1];       for (i = 2; i <= n; i++) {         if (a[i] >= last) {           last = a[i];           continue;         }         ans = max(ans, get_bit(last - a[i]));       }       printf( %d n , ans);     }     return 0;   }   