public static void main ( String [ ] args ) throws IOException {
  Scanner sc = new Scanner ( System . in ) ;
  int t = sc . nextInt ( ) ;
  while ( t -- > 0 ) {
    int n = sc . nextInt ( ) ;
    Long [ ] ar = new Long [ n ] ;
    for ( int i = 0 ;
    i < n ;
    i ++ ) {
      ar [ i ] = sc . nextLong ( ) ;
    }
    Long curMax = Long . MIN_VALUE ;
    Long max = Long . MIN_VALUE ;
    for ( int i = 0 ;
    i < n ;
    i ++ ) {
      if ( ar [ i ] > curMax ) {
        curMax = ar [ i ] ;
      }
      if ( ar [ i ] < curMax ) {
        max = Math . max ( curMax - ar [ i ] , max ) ;
      }
    }
    int ans = 0 ;
    for ( int i = 0 ;
    i <= 32 ;
    i ++ ) {
      Long x = ( long ) Math . pow ( 2 , i ) ;
      if ( x <= max ) {
        ans ++ ;
      }
      else {
        break ;
      }
    }
    System . out . println ( ans ) ;
  }
}

public static void main ( String [ ] args ) throws IOException { Scanner sc = new Scanner ( System . in ) ; int t = sc . nextInt ( ) ; while ( t -- > 0 ) { int n = sc . nextInt ( ) ; Long [ ] ar = new Long [ n ] ; for ( int i = 0 ; i < n ; i ++ ) { ar [ i ] = sc . nextLong ( ) ; } Long curMax = Long . MIN_VALUE ; Long max = Long . MIN_VALUE ; for ( int i = 0 ; i < n ; i ++ ) { if ( ar [ i ] > curMax ) { curMax = ar [ i ] ; } if ( ar [ i ] < curMax ) { max = Math . max ( curMax - ar [ i ] , max ) ; } } int ans = 0 ; for ( int i = 0 ; i <= 32 ; i ++ ) { Long x = ( long ) Math . pow ( 2 , i ) ; if ( x <= max ) { ans ++ ; } else { break ; } } System . out . println ( ans ) ; } }
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