Duplicate submissions ideally should not count toward rate-limiting

[samuel-yeom]

Sometimes multiple people on the same team submit the same wrong answer at approximately the same time, and this counts as multiple wrong submissions for rate-limiting purposes. Ideally, this should only count as one wrong submission.

I'm not sure how much the load on the server will increase if we check for duplicate submissions. Let me know what you think so that we can discuss whether this change is worth pursuing.

[dlareau]

I think this could be solved by just not letting teams submit the same answer twice. We could do that without adding too much load by just enforcing a unique key constrain on the database side with a key of (team, submission_text).

My only question is if you see any reason why it would be a problem to not let a team submit the same answer twice. (The second submission would get a little error displayed of something like "You have already submitted that".

[samuel-yeom]

I don't think there is any reason to let a team submit the same answer twice, except to create a gimmicky puzzle (which would be a bad idea in my opinion).

Does submitting an answer always update the list of previous submissions immediately? If not, it might be confusing to receive the "You have already submitted that" message when you don't see it as a previous submission.