My Solution to ABAP Community Code Contest `ABAP is excellent `

[EnnoWulff]

When thomas.jung started the ABAP Community Code Challenge on February 28th, I first thought: Okay, this is not a big deal for an advanced programmer. But after the first solutions came up with "made it with 5 lines", this really challenged me to do this in one line. After some help of my friends pjl and 28f4b37a40894f18a22abc696b8154f4 I really made it in one line.

Solution

This is my solution:

"Explanation why ABAP has four unique characters and not three as expected:

"the second A is a cyrillic character which looks equal to "normal A" but has different unicode value



PARAMETERS p_text type string DEFAULT `ABАP  is excellent ` LOWER CASE.



"class (S)AP (C)ommunity (C)oding (C)hallenge (S)eries

CLASS scccs DEFINITION.

  PUBLIC SECTION.

    METHODS solve

      IMPORTING

        text          TYPE string

      RETURNING

        VALUE(result) TYPE string_table.

ENDCLASS.



CLASS test DEFINITION FOR TESTING RISK LEVEL HARMLESS DURATION SHORT.



  PUBLIC SECTION.

  PRIVATE SECTION.

    DATA cut TYPE REF TO scccs.

    METHODS setup.

    METHODS abap_is_excellent FOR TESTING.

    METHODS lorem_ipsum_dolor_sit_amet FOR TESTING.

    METHODS many_trailing_spaces FOR TESTING.

    METHODS many_leading_spaces FOR TESTING.

    METHODS many_space_in_the_middle FOR TESTING.

    METHODS complex FOR TESTING.



ENDCLASS.



CLASS scccs IMPLEMENTATION.

  METHOD solve.



    result = REDUCE string_table( "STRING_TABLE is the output...

             LET

               "clean the text from spaces

               text_wo_double_spaces = replace( regex = '(\s)(?=\1)' val = text  with = `` occ = 0 )

               "delete trailing and leading blanks

               cleaned_text = shift_left( val = shift_right( val = text_wo_double_spaces ) )

               "number of words is the number of blanks + 1

               num_words = count_any_of( val = cleaned_text sub = ` ` ) + 1 IN

             INIT

               "fill first result line with "number of words"

               lines = VALUE #( ( |Number of words: { num_words }| ) )

             " derive words via SEGMENT of cleaned string

             FOR word

             IN REDUCE string_table(

             INIT w = VALUE #( )

             "do read the words and store in table (equals SPLIT INTO TABLE)

             FOR i = 1 THEN i + 1 UNTIL i > num_words

             NEXT w = VALUE #( BASE w ( segment( val = cleaned_text index = i ) ) ) )

             NEXT lines = VALUE #(

               "transfer word-string to result table (BASE for keeping existing lines)

               BASE lines ( |Number of unique characters in the word: { word } - {

                    "now calculate number of distinct characters in each word

                    lines( REDUCE string_table(

                      "prepare the character table

                      INIT chars = VALUE string_table( )

                      "do aas many times as the word has characters; pos is the offset for current character

                      FOR pos = 0 THEN pos + 1 WHILE pos < strlen( word )

                      NEXT chars = COND #(

                        "if current character does not exist in character table,...

                        WHEN NOT line_exists( chars[ table_line = word+pos(1) ] )

                        "...then insert current character

                        THEN VALUE #( BASE chars ( word+pos(1) ) )

                        " otherwise keep current character table as it is

                        ELSE chars ) ) ) }| ) )  ) .



  ENDMETHOD.

ENDCLASS.



CLASS test IMPLEMENTATION.

  METHOD setup.

    cut = NEW #( ).

  ENDMETHOD.



  METHOD abap_is_excellent.



    cl_abap_unit_assert=>assert_equals(

        act = cut->solve( `ABАP  is excellent ` )

        exp = VALUE string_table(

           ( `Number of words: 3` )

           ( `Number of unique characters in the word: ABАP - 4` )

           ( `Number of unique characters in the word: is - 2` )

           ( `Number of unique characters in the word: excellent - 6` ) ) ).



  ENDMETHOD.



  METHOD lorem_ipsum_dolor_sit_amet .



    cl_abap_unit_assert=>assert_equals(

        act = cut->solve( `Lorem ipsum dolor sit amet` )

        exp = VALUE string_table(

           ( `Number of words: 5` )

           ( `Number of unique characters in the word: Lorem - 5` )

           ( `Number of unique characters in the word: ipsum - 5` )

           ( `Number of unique characters in the word: dolor - 4` )

           ( `Number of unique characters in the word: sit - 3` )

           ( `Number of unique characters in the word: amet - 4` )

            ) ).



  ENDMETHOD.



  METHOD many_trailing_spaces.

    cl_abap_unit_assert=>assert_equals(

        act = cut->solve( `start             ` )

        exp = VALUE string_table(

           ( `Number of words: 1` )

           ( `Number of unique characters in the word: start - 4` )

            ) ).

  ENDMETHOD.



  METHOD many_leading_spaces.

    cl_abap_unit_assert=>assert_equals(

        act = cut->solve( `             end` )

        exp = VALUE string_table(

           ( `Number of words: 1` )

           ( `Number of unique characters in the word: end - 3` )

            ) ).

  ENDMETHOD.



  METHOD many_space_in_the_middle.

    cl_abap_unit_assert=>assert_equals(

        act = cut->solve( `start          end` )

        exp = VALUE string_table(

           ( `Number of words: 2` )

           ( `Number of unique characters in the word: start - 4` )

           ( `Number of unique characters in the word: end - 3` )

            ) ).

  ENDMETHOD.



  METHOD complex.

    cl_abap_unit_assert=>assert_equals(

        act = cut->solve( `    one   two      thréé  ÄÖÜ  •••   ` )

        exp = VALUE string_table(

           ( `Number of words: 5` )

           ( `Number of unique characters in the word: one - 3` )

           ( `Number of unique characters in the word: two - 3` )

           ( `Number of unique characters in the word: thréé - 4` )

           ( `Number of unique characters in the word: ÄÖÜ - 3` )

           ( `Number of unique characters in the word: ••• - 1` )

            ) ).

  ENDMETHOD.



ENDCLASS.



START-OF-SELECTION.

  cl_demo_output=>display_data( NEW scccs( )->solve( p_text ) ).

To make it look more professional, I added some unit tests. 😉

I tried to explain each single statement inline as good as I was able to.

Although I used unit tests, clean code and only one line, I didn't make it to the finals. 😞

Maybe next time...

P.S.: Unfortunately I forgot to release this blog post... 😞

P.S.S.: here is the Current Community Coding Challenge

That also reminds me to complete the Advent Of Code 2019...