comefrom: <awangdev>246. Strobogrammatic Number_2.java
code: public boolean isStrobogrammatic(String num) {
          if (num == null || num.length() == 0) return true;
          if (num.length() == 1) return num.equals("0") || num.equals("1") || num.equals("8");
          List<Character> candidate = new ArrayList<>(Arrays.asList('0', '1', '8', '6', '9'));
          char[] charArray = num.toCharArray();
          for (int i = 0; i < charArray.length; i++) {
              if (!candidate.contains(charArray[i])) return false;
              if (charArray[i] == '6') charArray[i] = '9';
              else if (charArray[i] == '9') charArray[i] = '6';
          }
          StringBuffer sb = new StringBuffer(String.valueOf(charArray));
          String reversedNum = sb.reverse().toString();
          return num.equals(reversedNum);
      }
masked: public boolean var_0 ( String var_2 ) {
    if ( var_2 == null || var_2 . length ( ) == 0 ) return true ;
    if ( var_2 . length ( ) == 1 ) return var_2 . equals ( "0" ) || var_2 . equals ( "1" ) || var_2 . equals ( "8" ) ;
    List < Character > var_21 = new ArrayList < > ( Arrays . asList ( '0' , '1' , '8' , '6' , '9' ) ) ;
    char [ ] var_23 = var_2 . toCharArray ( ) ;
    for ( int var_24 = 0 ;
    var_24 < var_23 . length ;
    var_24 ++ ) {
      if ( ! var_21 . contains ( var_23 [ var_24 ] ) ) return false ;
      if ( var_23 [ var_24 ] == '6' ) var_23 [ var_24 ] = '9' ;
      else if ( var_23 [ var_24 ] == '9' ) var_23 [ var_24 ] = '6' ;
    }
    StringBuffer var_28 = new StringBuffer ( String . valueOf ( var_23 ) ) ;
    String var_31 = var_28 . reverse ( ) . toString ( ) ;
    return var_2 . equals ( var_31 ) ;
  }
  