Hello CodeForces!

After getting a great solve on today's problem D, I was viewing the contest leaderboard to see how my fellow contestants were doing. I was shocked to see that lebronjamal, an unrated user, was in 21st place. At first, I was deeply impressed. This is a far better performance than I'd managed in my near 6 months of competing.

However, a shadow was soon cast onto my respect for this user. When reviewing lebron's submissions after the contest, I noticed something puzzling. Their submission to problem E had the riddle seen below: while short, it seems surprising to me such a skilled user should take the time to write this rather than taking the head start on problem F.

Here is another riddle. I asked my favorite LLM, Claude's Opus 4.9, whether this could be evidence of unfair behavior. I've filled in the blanks with its solution. As you can see, it reads: "I cheated in this contest using artificial intelligence". If true, this is perhaps the most condemning piece of evidence so far.

Fellow contestants: leave a comment on this blog post with your thoughts. Should action be taken against this individual?

I am writing to document a pattern of behavior by the user tuanha that I believe merits careful review. My intention is not to make accusations beyond the available evidence, but rather to present observations that I believe are sufficiently unusual to justify an independent investigation by the Codeforces team.

The primary concerns include:

A pattern of contest performance that appears inconsistent with prior history. Statistical indicators that, in my view, are unusual enough to warrant further examination. Additional observations that I have collected and can provide upon request, including supporting graphs and contest data.

I understand that none of these observations alone prove misconduct. I also recognize that exceptional improvement is possible through legitimate effort. For that reason, I respectfully ask that the administration evaluate the available evidence using whatever internal tools, logs, and information are available to you.

I would also like to mention that I currently live in Albania. I include this only because I would appreciate that any investigation be handled confidentially and that my identity not be unnecessarily disclosed. I have no desire for public conflict and simply wish to report what I believe should be reviewed.

Thank you for your time and for your continued efforts to maintain the integrity of Codeforces competitions.

Dear Codeforces administration,

This appeal is being submitted on behalf of DavesHotChicken, whose permanent ban is deeply troubling and, from everything currently known, completely unjustified.

DavesHotChicken achieved an extraordinary result by finishing second in the world. Instead of recognizing an exceptional performance, Codeforces has apparently responded by permanently banning him and allowing his name to be treated as though he had committed some serious violation. That is a big accusation, and it is completely unacceptable for a competitor's reputation to be permanently smeared without clear evidence and a transparent explanation of what they supposedly did wrong.

Being unexpectedly successful is not evidence of cheating. A single outstanding performance should not be enough to destroy a competitor's reputation or remove them permanently from the platform. DavesHotChicken is fully capable of explaining his performance, his solutions, and his approach to the contest. If there is a specific concern or piece of evidence behind this ban, then it should be clearly identified and reviewed fairly.

We are asking for an immediate and serious reconsideration of this decision. DavesHotChicken deserves a fair review based on concrete evidence, not speculation based solely on the fact that he performed exceptionally well. If there is no conclusive evidence of a violation, the ban should be lifted immediately and his reputation restored.

The Codeforces community deserves a moderation process that is fair, transparent, and willing to correct mistakes. We sincerely hope this case will be reviewed with the seriousness it deserves.