#include <bits/stdc++.h>   int main() {     int t;     scanf( %d , &t);     while (t--) {       int n;       scanf( %d , &n);       std::vector<int> a(n);       for (int i = 0; i < n; i++) {         scanf( %d , &a[i]);       }       int minadd = 0;       int cur = a[0];       for (int i = 1; i < n; i++) {         if (cur > a[i]) {           minadd = std::max(minadd, cur - a[i]);         }         cur = std::max(cur, a[i]);       }       int nBits = 0;       while (minadd) {         nBits++;         minadd >>= 1;       }       printf( %d n , nBits);     }     return 0;   }   