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.↵
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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. ↵
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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:↵
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[There's a Cheater Among Us!](https://mirror.codeforces.com/blog/entry/138397)↵
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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 [user:aliqi,2026-01-12] 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 timetoas far as 6th place earning them first prize worth 8000 euros.↵
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This doesn't prove anything but I've decided to dig deeper and noticed that two more accounts mentioned in the blog, [user:onyeo,2026-01-12] and [user:kvtan,2026-01-12] 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".↵
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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.↵
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https://mirror.codeforces.com/blog/entry/138397#comment-1237360↵
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The commenter, [user:wltt,2026-01-12],also participated and who fiercely defended the accused cheaters, also participated in Huawei and earned a top 50 finish with a very small amount of submissions. I decided to check if there is some publicly written code by each of these accounts as you cannot view the submissions on either MaraTON or Huawei and what I found amazed me.↵
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I would like you to view these submissions by the following accounts:↵
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[user:wltt,2026-01-12] [submission:302430089]↵
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[user:aliqi,2026-01-12] [submission:321461102]↵
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[user:kvtan,2026-01-12] [submission:334862013]↵
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These are all submissions during an active rated contest that these accounts took part in. Do you notice something? The template, coding style, indentation all appears to be EXACTLY the same. I have rarely (if ever) seen a person to decrement/increment a variable with a space between, like i ++ or i --, but ALL THREE of these accounts seem to do just that in each of their submissions. Along with the other extreme similarities in the code and the entire context involving these accounts I think I can without a doubt claim that accounts [user:wltt,2026-01-12] [user:aliqi,2026-01-12] [user:kvtan,2026-01-12] are owned by the same person.↵
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Another example of extreme similarities between the accounts are the only comments left by the accounts [user:aliqi,2026-01-12] and [user:kvtan,2026-01-12] on the Codeforces site.↵
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[user:aliqi,2026-01-12] https://mirror.codeforces.com/blog/entry/137533#comment-1239087↵
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[user:kvtan,2026-01-12] https://mirror.codeforces.com/blog/entry/137533#comment-1238978↵
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Both seem to be extremely blatant AI written comments written one after another describing their approach to the MaraTON problem.↵
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I think this case goes beyond usual cases of cheating as large amounts of prize money are in question. I expect something to be done about this as this is an insult to all legitimate contestants who spent hours and days on the contest only to have their spots taken in the last hours of the contest by this multi accounter.↵
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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:↵
↵
[There's a Cheater Among Us!](https://mirror.codeforces.com/blog/entry/138397)↵
↵
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 [user:aliqi,2026-01-12] 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
↵
This doesn't prove anything but I've decided to dig deeper and noticed that two more accounts mentioned in the blog, [user:onyeo,2026-01-12] and [user:kvtan,2026-01-12] 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↵
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The commenter, [user:wltt,2026-01-12],
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I would like you to view these submissions by the following accounts:↵
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[user:wltt,2026-01-12] [submission:302430089]↵
↵
[user:aliqi,2026-01-12] [submission:321461102]↵
↵
[user:kvtan,2026-01-12] [submission:334862013]↵
↵
These are all submissions during an active rated contest that these accounts took part in. Do you notice something? The template, coding style, indentation all appears to be EXACTLY the same. I have rarely (if ever) seen a person to decrement/increment a variable with a space between, like i ++ or i --, but ALL THREE of these accounts seem to do just that in each of their submissions. Along with the other extreme similarities in the code and the entire context involving these accounts I think I can without a doubt claim that accounts [user:wltt,2026-01-12] [user:aliqi,2026-01-12] [user:kvtan,2026-01-12] are owned by the same person.↵
↵
Another example of extreme similarities between the accounts are the only comments left by the accounts [user:aliqi,2026-01-12] and [user:kvtan,2026-01-12] on the Codeforces site.↵
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[user:aliqi,2026-01-12] https://mirror.codeforces.com/blog/entry/137533#comment-1239087↵
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[user:kvtan,2026-01-12] https://mirror.codeforces.com/blog/entry/137533#comment-1238978↵
↵
Both seem to be extremely blatant AI written comments written one after another describing their approach to the MaraTON problem.↵
↵
I think this case goes beyond usual cases of cheating as large amounts of prize money are in question. I expect something to be done about this as this is an insult to all legitimate contestants who spent hours and days on the contest only to have their spots taken in the last hours of the contest by this multi accounter.↵
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