Hello, in this post I will describe what I believe to be a very severe and elaborate case of cheating that took place on the just recently finished ICPC 2025 Online Winter Challenge powered by Huawei contest.
For context, the challenge is a 16 day contest with a large prize pool where contestants solve one optimization problem and aim for a score as high as possible. On the last day of the contest (precisely the last 6 hours), I was very surprised to find that multiple unrated accounts or accounts with minimal activity and background were able to unexpectedly replace the previous top scorers, earning them the places worthy of the first (8000 eur) or second (3000 eur) prize.
I was interested to learn who these brilliant competitors were since their profile gave me no information so I tried to google their usernames, mostly ending up with no results but one in particular led me to this very interesting blog on Codeforces about suspected cheaters on MaraTON Challenge 1 (also a contest with one optimization problem and a large prize pool) that took place about 1 year ago:
Before proceeding further, I would like you to first read the blog post I've linked. You may recognize one handle from the post if you participated in the Huawei contest. Namely, the 6th place in Huawei contest aliqi is mentioned as one of the suspected cheaters in the MaraTON contest. Interestingly they followed the same pattern in both contests, after sending a few weak solutions, they unexpectedly skyrocket to top scores, only this time to 6th place earning them first prize worth 8000 euros.
This doesn't prove anything but I've decided to dig deeper and noticed that two more accounts mentioned in the blog, onyeo and kvtan also participated in the Huawei challenge and placed in the top 50, both with the same pattern of "send a few weak solutions and then suddenly a brilliant one in the last hours of the contest".
Still this is not yet proof of anything, but the final twist came when I decided to read the comments of the MaraTON cheaters blog and one in particular caught my attention.
https://mirror.codeforces.com/blog/entry/138397#comment-1237360
The commenter, wltt, also participated and
