By randomly looking at the submissions from the last rounds, I discovered the fact of the cheating by the user Dedalius. The automatic anti-cheat system did not detect this. However, if you carefully look at the submissions of this user, you will find a lot of useless code. Interested in this fact, I found the original author of these codes. It was user Tematop.
You can see the coinciding time of the submissions, and also below there are the submissions of users.
To hide the fact of cheating, Dedalius used useless code.
By comparing the submissions, you can notice the obvious fact of cheating. If you look at more packages, it becomes clear that this is not the first case of cheating on contests!