The author is breaking the rules of HackerRank and should (hopefully will) be banned.
Anytime we share challenge problem solutions in the open there is an ethical issue about it. HackerRank specifically even does plagiarism detection.
I some of my own solutions to challenge questions in a public repo on GitHub [1] for educational purposes. I recently slapped a big disclaimer on that for people like this.
> Disclaimer: These solutions were developed by me individually unless otherwise stated and are shared for education and curiosity. Please do not use them as your own. If you're working on the same problem, please do not view my answer until you've solved it on your own. If you're working on a related problem, it's generally okay to cite a solution to another problem as a reference.
There is already an ethical issue, anyway you look at it. Even if you do not copy paste the answers.
Its not like participants on forums like hackerrank invented those algorithms. Every single data structure and algorithm question asked on sites like hackerrank has solutions invented by some Computer Scientists, participants are just using them.
The only question we are asking from the where do those participants replicate the answers? Do they replicate it from a book? Webpage? Memory? You could replicate the answer from anywhere, as long you didn't invent the data structure or the algorithm you are essentially plagiarizing.
>>HackerRank is a technical recruiting platform.
If you use irrelevant tests to measure capability of the candidates, why cry when they match up to it in their own way?
Writing your own algorithm or data structure implementation from a description of the algorithm is considered fair game in every programming challenge competition I've ever seen. This includes the national level ones like ACM.
> Anytime we share challenge problem solutions in the open there is an ethical issue about it
I disagree, in fact, I hate it when I cannot find a solution to certain problem because I don't care about the Internet points but I do care about the learning. Usually when I am solving those coding problems I do it by myself but when I get stuck I want to see the solution right away, analyze it, then open WikiPedia, some books, and understand why the solution is like that, then close the window and try to resolve the exercise by myself once again in 2-3 days. If I cannot find the solution then I get stuck on that step and cannot learn at all (unless I invest a 3x the time to understand the jargon from WikiPedia/books).
CodeWars, for example, does something similar. They let you see the solutions from other participants and people can vote for the best/clever/optimized ones. However, these solutions are still hidden and you can only see them after you solve the exercise by yourself which is still a problem.
I agree with the other comment that there is no ethical issues here, that is just an overreaction.
Anytime we share challenge problem solutions in the open there is an ethical issue about it. HackerRank specifically even does plagiarism detection.
I some of my own solutions to challenge questions in a public repo on GitHub [1] for educational purposes. I recently slapped a big disclaimer on that for people like this.
> Disclaimer: These solutions were developed by me individually unless otherwise stated and are shared for education and curiosity. Please do not use them as your own. If you're working on the same problem, please do not view my answer until you've solved it on your own. If you're working on a related problem, it's generally okay to cite a solution to another problem as a reference.
[1]: https://github.com/tedmiston/challenges