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Thomas Jung

February 28, 2020 2 minute read

SAP Community Coding Challenge Series

It is with great pleasure that we announce a new community activity – the SAP Community Coding Challenge Series. The idea is that periodically SAP will post a coding challenge or puzzle for the community to solve. It will be something fun yet hopefully will teach something as well. It should be simple enough that most people could work on it over a lunch break but if you really want to solve the problem optimally might require some thoughtful research and experimentation.

For this first challenge, we will go to our technology roots in the SAP community and open with an ABAP coding challenge. This challenge can be performed in the SAP Cloud Platform ABAP Environment Trial (this is where our sample solution was tested).

https://developers.sap.com/tutorials/abap-environment-trial-onboarding.html

Voting is now LIVE!

To vote on the winner, simply go to this Community question. The finalist are all listed as answers. Upvote the answer you believe is best.

https://answers.sap.com/questions/13007129/sap-community-coding-challenge-march-2020.html

And if you want more details on the Special Award winners, Rich Heilman posted a blog about them here: https://blogs.sap.com/2020/03/17/sap-community-coding-challenge-series-march-2020-special-awards/

Midpoint Challenge Update:

Now that we are 1/2 way through the first challenge, we did a live stream to discuss the progress, judging and how to get started coding in the SAP Cloud Platform ABAP Environment Trial.

Challenge Directions:

Start with this line of code as the first line in your application. Requirement: make sure to cut and paste this line of code and NOT type it.

    DATA(sentence) = `ABАP  is excellent `.

Using the value in the variable sentence, programmatically determine the number of words in this variable and then count the number of UNIQUE letters in each word.

Your output should look like this:

The goal is to accomplish the task with as few lines of code as possible. Our sample implementation uses 9 lines including the data(sentence) and out->write lines. Can you do it in less?

Consider processing efficiency and ABAP best practices as well. How clean is your code? https://github.com/SAP/styleguides/blob/master/clean-abap/CleanABAP.md Usage of Hungarian notation will be severely ridiculed. ?

Finally you must also explain why ABАP correctly has 4 unique letters.

Submission and Judging

Once you have a solution you are happy with, please email your submissions along with a link to your public SAP Community Profile to the community@sap.com inbox. Everyone has until March 15th, 23:59 Pacific Daylight Time (PDT) / UTC-7 to submit your coding solution. The community and developer advocates team at SAP will then do the first round of judging, narrowing down to 5 finalist that have the cleanest, most elegant, or most creative solutions. We will then post these 5 finalist in a community Q&A entry so that everyone will have a chance to vote on the best overall solution.

In the spirit of the immortal Stan Lee, the fabulous prize for the winner of the Coding Challenge will be a No-Prize. The coveted No-Prize also comes with the unending adulation and admiration of the community of fellow developers.

69 Comments

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Mohammad Saif

February 28, 2020 at 5:49 pm

Hi Thomas,

Good initiative. Really appreciate it. And also "No-Prize" Haha

Kesari Katakam

February 28, 2020 at 6:10 pm

Number of Unique characters in ABAP - 4 ??

Thomas Jung

Blog Post Author

February 28, 2020 at 6:50 pm

Yes – that’s part of the challenge to figure why that is the case. 😉

Kesari Katakam

February 28, 2020 at 7:06 pm

Sure some thing is 'special' in ABAP there 😉

Robin Wagner

March 3, 2020 at 10:23 am

This is why you should copy the "DATA(sentence)"-line 😉

Enric Castella Gonzalez

February 28, 2020 at 11:49 pm

Great challenge and magical award!

Vicky Khambhati

February 29, 2020 at 5:44 am

I stopped doing ABAP 7 years ago.. but this excites me. Specially, ABAP - 4 ?

I think, I should give a try and see how much developer left in me?

Promise Aphana

February 29, 2020 at 2:02 pm

Hi Thomas,

Does the 9 lines include blank lines for neat formatting?

Thomas Jung

Blog Post Author

February 29, 2020 at 2:17 pm

No we are only counting lines of code.

Stephan Köster

February 29, 2020 at 5:28 pm

Nice challenge. It's possible with 8 lines of Code.

Stephan Köster

March 5, 2020 at 8:15 pm

Clean Code? Challenge accepted. 😉

Frederic Girod

March 6, 2020 at 2:00 pm

Clean code does not means Clean writed. It means you follow all the rules

https://github.com/SAP/styleguides/blob/master/clean-abap/CleanABAP.md

Do one thing, do it well, do it only

you do a loooot of things

Klaus Steinbach

February 29, 2020 at 8:26 pm

Dear Thomas,

as I love automated unit testing some questions to your requirement:

Do we only talk about alphabetic letters (A-Za-z) which can make up a word or also numbers (0-9) and other letters (!"§...) but not separated by any space like characters?
Shall it also work for other languages as like chinese, arabic, etc.?
Do we talk about case-sensitive or case-insensitive?
are we allowed to use helper classes like cl_demo_output or only out->write?

Love the challenge!

Cheers Klaus

Thomas Jung

Blog Post Author

February 29, 2020 at 8:44 pm

Characters not letters

yes

upper/lower would be different characters

Your choice. We didn’t specify how to produce the output. The calculation itself is what we are after

Klaus Steinbach

March 1, 2020 at 12:38 am

Awesome challenge. Learned something new and would say it is possible in 6 statements. The ABAP case with 4 chars nice trick 🙂 Looking forward to your judgement.

Bärbel Winkler

February 29, 2020 at 9:16 pm

I love a challenge but am wondering: is it solvable (without using brute force) on a NW 750 EHP 8 system or are newer ABAP syntax options needed to get it done in as few lines of code as possible?

Cheers

Bärbel

Thomas Jung

Blog Post Author

February 29, 2020 at 9:29 pm

I’m sure it’s solvable there but might require a few more lines of code. Of course if you want to use the newest syntax, the SAP Cloud Platform ABAP Environment Trial is an easy solution.

Uwe Fetzer

March 3, 2020 at 1:59 pm

I have a running code on 7.40 SP8 with just three lines of code -> so yes, it's possible on older releases

Peter Jaeckel

March 4, 2020 at 12:23 am

One line for the assignment, one for the split and one for the rest?

Uwe Fetzer

March 4, 2020 at 6:05 am

Mahesh Palavalli

March 1, 2020 at 7:41 am

wrapping of a single line to multiple lines is still considered a single line right? <Limitation of ABAP 255 chars in a single line>

Thomas Jung

Blog Post Author

March 1, 2020 at 12:59 pm

Yes. It’s fine to break a single line of code over multiple lines in the editor. That improves readability which is also an important factor here.

Frederic Girod

March 2, 2020 at 1:23 pm

I am not sure to be able to do it better. And I have a CHECK … a LOOP …

but, it is dynamic, unreadable, … perfect developer code 🙂

And there is no hungarian notation ( for Matthew Billingham )

Bärbel Winkler

March 2, 2020 at 2:42 pm

Not to be a spoilsport, Fred - but shouldn't "Number of words" be 3? ?

Frederic Girod

March 2, 2020 at 2:47 pm

A yes ... need to move my check 🙂

Frederic Girod

March 2, 2020 at 5:54 pm

After the good remark of Bärbel Winkler, I have to change the code, I replace a line by another line. So same score

Florian Henninger

March 2, 2020 at 6:57 pm

MAybe there are other reasons 🙂

Robin Wagner

March 3, 2020 at 10:24 am

6 lines of code, beat me! 😀

Jacek Wozniczak

March 3, 2020 at 3:03 pm

As Thomas said on Twitter "Until you hit the period it’s one line of code even if spread across multiple lines in the editor" I got 4 lines of super modern, dirty, expression-style nightmare code I made just as an exercise 😀 [as opposite to my elegant solution].

Sreenivasan Ravi

March 5, 2020 at 3:37 pm

If that the case, I got 3 lines of code. I don't know how my code works 🙂

jonathan albert

March 3, 2020 at 6:13 pm

Hi Thomas,

I have a doubt, in the challenge they say nothing about the use of classes that attend to solve the problem, but if I use a method that has 20 lines of code that solve the problem, 1 line of code is counted by the method call or 20 lines of code for the implementation of the method?

Thomas Jung

Blog Post Author

March 3, 2020 at 6:23 pm

Well did you write the class or your reusing something supplied by the platform? But in the end I hope people aren't getting too tied up in the lines of code. I called that out mostly to challenge people to think of more inventive ways of solving the problem than just brute force approaches. Hopefully this gives you an opportunity to research some syntax that is new to you. Elegance, readability, maintainability are all factors as well. We will only use these criteria to narrow down to the finalist. Ultimately the community will vote on the winner.

Frederic Girod

March 4, 2020 at 12:14 pm

I think the sentence

The goal is to accomplish the task with as few lines of code as possible

make the chalenge based on the number of lines.

Maybe next time, we could have "Clean Code Challenge".

Thomas Jung

Blog Post Author

March 4, 2020 at 1:39 pm

The next paragraph does add to that:

But point taken that people have taken to the lines of code aspect a bit more than I had personally intended. I was hoping that aspect would push people to explore some new ABAP syntax (which seeing the submissions it certainly has). Its one of several interesting aspects for people I hope. But we will be sure to balance or rotate the challenge modifiers in the future.

Thomas Jung

Blog Post Author

March 4, 2020 at 1:41 pm

I'll add that I've been really impressed by how many unique and creative approaches there have been in the submissions. I think the community is going to have lots of fun looking at them once the submission period is over.

Frederic Girod

March 5, 2020 at 8:48 am

Done !

It was easier in Clean Code / more readable

So if I don't count the class/method/.. lines, I am now with 7 lines.

It is interesting to see, with the same number of lines, but with Class & methods, the code is simpler.

Frederic Girod

March 4, 2020 at 1:57 pm

Do you think I could propose a Clean-Code answer if I have already send my proposal ?

Thomas Jung

Blog Post Author

March 4, 2020 at 2:06 pm

Sure there was no rule against multiple submissions. Others have done so.

Mahesh Palavalli

March 4, 2020 at 2:56 pm

I've sent like 4 mails till now 😀 (Continuously every day !!)

Mahesh Palavalli

March 4, 2020 at 3:04 pm

Exactly, if there was no mention of no of lines, I sure would have not taken it as a challenge 😉

Just because of that criteria, I tried different ways and used many new functions and syntax. It sure was a fun learning experience for me 😀 ,

one of my colleague saw me doing this today and she started to learn about constructor expressions, reduce, for, e.t.c, to do this challenge.

With normal abap, surely we cannot do it in less lines, we have to use some new features to do this. maybe 2 categories would be nice, one with Clean ABAP and one with less lines. So people can push both ways.

jonathan albert

March 4, 2020 at 5:18 pm

Yes i think that the idea of Master Thomas is that we look 
for new ways to do it, not only using the old sentences 
that we are used to using. I personally have had to 
investigate many sentences that I did not know and 
I think that is the objective of the challenge, 
to challenge the knowledge we already have in order 
to be better. Thanks to Master Thomas and team.

Sandra Rossi

March 3, 2020 at 7:53 pm

I did it with 2 lines of code including the initial line, but one line for everything is just madness, especially the logic to count unique characters… The choice of auxiliary variable names is essential to make the code understandable. And if you do it “right” by using translatable texts, that’s even more madness ?

Frederic Girod

March 4, 2020 at 4:24 am

we need to discuss ! 😉

How could you split without split ... or how could you split & use directly the result .. ??

Mahesh Palavalli

March 4, 2020 at 5:05 am

I wouldn’t say it is madness, It’s more like an art :P, I’ve sent the code both with 1 line(included data declaration inside) and 2 lines with separate data declaration.

but have you done that using regex?

Sandra Rossi

March 4, 2020 at 8:11 am

Frederic Girod Mahesh Kumar Palavalli The answer is simple: what solution other than SPLIT can you use? Of course, the issue with doing it in one statement is that fellow developers who will maintain the code need to master many aspects of the ABAP language, including the regular expressions which are widely adopted in many languages, understand very well the constructor expressions. It's often not the case, so my code fits "shortest" but doesn't fit "Elegance, readability, maintainability".

Frederic Girod

March 4, 2020 at 8:37 am

I have tried REGEX ... but ...

Bravo !!

Frederic Girod

March 4, 2020 at 4:20 am

I cannot see how it could be Clean-Coded. We do several actions in the same set of code lines.

Mahesh Palavalli

March 4, 2020 at 5:08 am

it's not clean for sure unless we format it into multiple lines, but without the .(dot).. then it is still a single line 😛

Sai Kowluri

March 6, 2020 at 9:51 pm

Less lines of code is often confused with clean code. To me, clean code should be easy to read and easy to troubleshoot by anyone other than the author.

Frederic Girod

March 9, 2020 at 6:29 am

I am not agree, Clean Code is easy to maintain, it is the main objective. Check the SOLID principle.

We create more class/interfaces with sometimes design pattern. It is not easy to read.

Oleg Bashkatov

March 4, 2020 at 4:04 pm

Could I exclude the line

DATA(sentence) = `ABАP  is excellent `.

but pass the string as a parameter to out ?

Thomas Jung

Blog Post Author

March 4, 2020 at 4:10 pm

Yes as long as you start with that string literal and be sure to still cut and paste to pickup some of the "special" conditions we created in that string.

Oleg Bashkatov

March 4, 2020 at 4:19 pm

Thanks! it will save one line and increase readability.

Enno Wulff

March 5, 2020 at 5:49 pm

One "line" of code.

cl_demo_output=>display
                  REDUC
                  LET s
                      s
                      n
                  INIT 
                  FOR w
                  IN RE
                  INIT 
                  FOR i
                  THEN 
                  UNTIL
                  NEXT 
                  NEXT 
                  BASE 
                  lines
                  REDUC
                  INIT 
                  FOR p
                  NEXT 
                  WHEN 
                  THEN 
                  ELSE

now working a bit on clean code... 😀

Peter Jaeckel

March 7, 2020 at 12:14 pm

thanks for the discussion, I have it now in one line as well. I thought it might be overkill to replace the split by reduce expression. but its okay. We should compare results next time.

Enno Wulff

June 4, 2023 at 8:38 pm

better late than never.

this is my result

    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 ) ) ) }| ) )  ) .

Jörg Wulf

June 15, 2023 at 4:38 pm

I have to admit, that one poked at my ambitions. So here's my version of a one-liner:

cl_demo_output=>new(                                              "make use of output class
  )->write( REDUCE string( LET sentence = `ABАP  is excellent `   "Why waste a data statement?
                               rgx_word = '\w+'                   "regular expression matches word
                               rgx_unique_char = '(.)(?!.*\1)'    "regular expression matches unique 
                                                                  "characters
                               mx      = count( val   = sentence 
                                                regex = rgx_word )      "count the words with regexp
                               content = VALUE string_table( FOR c = 1  "for the table
                                                             THEN c + 1 "initialization
                                                             UNTIL c GT mx               
                                        ( match( val   = sentence       "in order to get them separated
                                                 regex = rgx_word 
                                                 occ   = c ) ) ) IN 
                           INIT text = |Number of words: { mx }|
                             FOR i = 1 THEN i + 1 UNTIL i GT mx       "loop the words
                             NEXT text = text && |\rNumber of unique characters in the word: { 
                                                  content[ i ] } - {  "every word-output starts 
                                                                      "with new-line
                             count( val = content[ i ] regex = rgx_unique_char )  "counting unique 
                                                                                  "Characters with regexp
                                   }| ) )->display( ).                "finally producing the output

Enno Wulff

June 15, 2023 at 4:54 pm

Wow! That one looks really neat and elegant Jörg Wulf ! 👍

Stephan Heinberg

March 6, 2020 at 7:39 am

Thanks, Thomas for the challenge. Great, I didn’t know, you still do ABAP.
There is no plain text ;->

Pierre COL

March 6, 2020 at 5:44 pm

Having created the SAP Intelligent RPA Tutorials Challenge which ended Feb 29th, I totally support this very good initiative and I wish I knew ABAP programming to participate!

Kudos Thomas Jung!

Thomas Jung

Blog Post Author

March 6, 2020 at 5:51 pm

Its never too late to start learning ABAP 🙂

Pierre COL

March 6, 2020 at 8:07 pm

You are definitely right: I started programming computers in 1978, being 15yo, and it was Z80 assembler, so, indeed, why not ABAP? ?

Sai Kowluri

March 6, 2020 at 10:00 pm

Thanks for this Thomas.

Vishnu Gudi

March 13, 2020 at 12:07 am

I did it with 13 lines of code with basic abap, let me cutdown number of lines.

James Bungay

March 17, 2020 at 9:08 pm

Hi guys,

Below is my simplified version for anyone interested. A little Reduce and some regex.

Neat challenge, can't wait for the next one.

Cheers,

James

CLASS ycl_sap_cc_20200228_dirty DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC .

PUBLIC SECTION.
    interfaces if_oo_adt_classrun.
PROTECTED SECTION.
PRIVATE SECTION.
ENDCLASS.

CLASS ycl_sap_cc_20200228_dirty IMPLEMENTATION.
  METHOD if_oo_adt_classrun~main.
    DATA(sentence) = `ABАP  is excellent `.

    data(number_of_words) = count( val = condense( sentence ) regex = `(\b[^\s]+\b)` ).

    out->write( reduce stringtab(
                init output = value #( ( |Number of words: { conv string( number_of_words ) }| ) )
                     word type string
                     number_of_unique_characters type i
                for index = 1 until index > number_of_words
                next word = segment( val = sentence index = index space = ` ` )
                     number_of_unique_characters = count( val = word regex = `(\S)(?!.*\1.*)` )
                     output = value #( BASE output ( |Number of unique characters in the word: { word } - { conv string( number_of_unique_characters ) }| ) ) ) ).
  ENDMETHOD.
ENDCLASS.

Guilherme Gaino Galindo

March 17, 2020 at 9:34 pm

I’ve made a simple solution, using two REDUCE operations, no more than that. I believe most people went for that, or using LOOP, FOR, DO, etc., the result is the same. I thought about doing sorted tables, select, char/number calculation, or even Regex. But favored the REDUCE one. Nice to see different approaches for the same problem.

Tomas Buryanek

March 19, 2020 at 3:10 pm

Hi,

I just found this challenge blog. Love the announcement video stream where you two comment on the submitted code! Funny reactions and comments on regex etc. Relatable 🙂

I will try get up to date with blogs and hopefully join some of the upcoming challenges.

Angel Pachon Solana

April 22, 2020 at 1:26 pm

Great challenge!

Andrei Touzik

June 6, 2020 at 8:55 pm

One more solution

  METHOD if_oo_adt_classrun~main.
    DATA(sentence) = `ABАP  is excellent `.
    SPLIT condense( sentence ) AT space INTO TABLE DATA(words).
    out->write( |Number of words: { lines( words ) }\n| && REDUCE #( INIT s = `` FOR <word> IN words NEXT s = s &&
    |Number of unique characters in the word:  { <word> } - { REDUCE #( INIT c = 0 r = <word> FOR i = 0 WHILE i < strlen( <word> )
    NEXT c = c + COND #( WHEN count( val = r regex = <word>+i(1) ) > 0 THEN 1 ) r = replace( val = r sub = <word>+i(1) with = `` occ = 0 ) ) }\n| ) ).
  ENDMETHOD.

Event Information

SAP Community Coding Challenge Series

Voting is now LIVE!

Midpoint Challenge Update:

Challenge Directions:

Submission and Judging

Assigned Tags