Hello Codeforces Community and MikeMirzayanov, Recently,I and two of my friends shrek1234 and arnavra3 ,received a plagiarism warning on Codeforces for a problem we independently solved during a contest. We were surprised and confused to see that our codes had been flagged as matching, despite the fact that none of us discussed or shared any part of the solution during the contest.
We believe we are innocent – and here’s why:
The Problem Was Simple* The problem in question had a straightforward logic, and our implementation didn’t require any particularly creative tricks or unique code structures. As a result, it is very plausible that several solutions – written independently – would end up looking similar in structure, variable names, and flow.
For instance, if the optimal solution only needs:
- A single loop,
- A few conditionals,
And maybe some sorting or a greedy strategy...
Then the implementation space is naturally small. Many participants – especially those of similar skill levels and habits – may write strikingly similar code without any communication whatsoever.
The Real Issue – Detection Sensitivity The plagiarism detection system appears to heavily penalize structural similarity and perhaps token-level matches, even when the actual possibility of collaboration is practically zero.
What’s more concerning is that we know participants who:
- Copied entire code templates or solutions from ChatGPT or online sources,
- Made slight modifications (like changing loops or variable names),
- And still weren’t flagged.
This creates an unfortunate scenario where:
- Honest participants get punished for coincidence, and
- Actual cheaters manage to escape detection with minimal effort.
This is not just about our rating or our profiles. It's about keeping the spirit of Codeforces fair and strong. If the system makes too many false positives, it could discourage honest coders and create a sense of injustice.
We also request the setters bashkort and TheEvilBird to look into the issue and review our submissions once.
The submission links are: - Shrek1234: https://mirror.codeforces.com/contest/2113/submission/324501156 — Slamix:https://mirror.codeforces.com/contest/2113/submission/324476418 Arnavra3:https://mirror.codeforces.com/contest/2113/submission/324510734
We urge the Codeforces community to highlight this problem which can happen to anyone and help build a better and fairer platform together.
