If I check on archive https://web.archive.org/web/20200921030437/https://github.co... it doesn't look like this repo should be dmca ed.
They also seem to claim copyright on renditions of "their" questions in various repositories containing interview notes in general, e.g. https://github.com/jayshah19949596/CodingInterviews/blob/mas...
There's also a number of URLs in here which have "leetcode" and not "hackerrank" in them.
A sibling points out this golden nugget from the DMCA notice: "(the whole repository is infringing copyright as it contains the solution)" i.e. HackerRank is claiming that not only they own the copyright on "How to find the first occurrence of x in s?" but also every solution to that question, which is a completely ridiculous notion.
They are in hiring business not CS education business. Their business is not helping people learn things, but helping companies hire people.
If the solutions are available online, anybody can memorize them and ace tests, And they often do. If too many people do it, the whole point of test is defeated. The more solutions are available online, the more pointless the test becomes. Which actually says more about the testing methods themselves.
On the other hand, it's realistically impossible to keeping coming up with questions that can genuinely test a person's ability to come up with a novel algorithm for a problem. That's a CS PhD at least, if not a Fields medal category problem.
Protecting a business model such as HackerRank's was not the intention of copyright or the DMCA. Your argument almost turns the entire idea of copyright on it's head.
As I read your comment I take away a point of view of:
The HackerRank business model is predicated on keeping other peoples copyrighted work out of the hands of potential users, therefore HackerRank should be entitled the copyright of these other people.
That is not a viewpoint I could support and I don't believe many, other than HackerRank could support it either.
Just be glad, they haven't yet patented or copyrighted a tree, graph or a linked list yet.
Wrote a tree traversal program to solve some problem in your program? Sorry that connects to some problem they own, so now your solution belongs to them.
(Not bringing up the discussion, just mentioning it.)
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