comefrom: <qiyuangong>482_License_Key_Formatting_1.java
code: public String licenseKeyFormatting(String s, int k) {
          StringBuilder sb = new StringBuilder();
          for (int i = s.length() - 1; i >= 0; i--)
              if (s.charAt(i) != '-')
                  sb.append(sb.length() % (k + 1) == k ? '-' : "").append(s.charAt(i));
          return sb.reverse().toString().toUpperCase();
      }
masked: public String var_0 ( String var_1 , int var_2 ) {
    StringBuilder var_3 = new StringBuilder ( ) ;
    for ( int var_4 = var_1 . length ( ) - 1 ;
    var_4 >= 0 ;
    var_4 -- ) if ( var_1 . charAt ( var_4 ) != '-' ) var_3 . append ( var_3 . length ( ) % ( var_2 + 1 ) == var_2 ? '-' : "" ) . append ( var_1 . charAt ( var_4 ) ) ;
    return var_3 . reverse ( ) . toString ( ) . toUpperCase ( ) ;
  }
  