[aerojoe23]

The hashes will sum to something. To do it, at least as far as I understand, you'd have to use https://git-scm.com/docs/git-filter-branch . This will create a divergent history and the new master branch or any other branches that exists will have to be forced pushed. As far as "but local copies of the repo will have the 'problem files' still" - Yes they would. All parties would have to be notified of the legal request.

I'm not a copyright expert but it seems like enforcing this is another step in the erosion of fair use. Something about transformative works. The problem was transformed into a solution.

On the other hand hackerrank's terms of service should have banned this activity. I would imagine it does. I'm not sure how much leverage that gets them legally though. I suppose once you intend to publish it you're no longer an authorized user, and then you're violating that https://en.wikipedia.org/wiki/Computer_Fraud_and_Abuse_Act we see get applied harshly from time to time.