When a moderator becomes a Cheater, a Theft, a Loser

@CyberLemonade, your Java solution was copied and used by O... to finish 3xN Tiling.

My respected @JBM, your perl solution was copied and used by .H.. to finish Goro Want Chocolate

The talented @Niako, your Python3 solution was copied and used by
..E. to finish Photo Booth Transformation.
Your Python3 solution was stolen too, for finishing Cloudy Weather.

@Wei-1, your Scala solution was copied and used by ...R to finish Basic Decision Tree2

@LaurentBouvier, your Python3 solution was copied and used by .{4} to finsih Nonogram Inversor

Math master @Nicola, your Python3 solution was copied and used by [A-Z]{4} to finish Factorials of Primes Decomposition.

@VilBoub, your Python3 solution was copied and used by ^O.* to finish Squares Order.

@Alain-Delpuch, your Javascript solution was copied and used by .*R$ to finish The Total is Right - Weird Edition

Even the honorable @player_one’s C# solution was copied and used to finish Breakout.

Do I need to list more?

I don’t mind knowledge sharing but strictly hate Plagiarism.


Hope they find Scala a great programming language during the copying process. :rofl:


Also Shikaku Solver. It is scandalous!

Yes, there are a lot of cases like that. It is so easy to click on “view contribution” to copy / paste the author’s solution just to have more XP and satisfy their ego, without having to do any effort to find a solution themselves … but they just learn absolutely nothing.

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I just plagiarized ??? by anticipation with this puzzle (and I got the idea on the famous les-maths.net forum). :grin:

Well apparently the person you point out has done that with almost all my other puzzles in the last few weeks. He’s not the only one though, I had already noticed a few other high-level people publishing my solution on my puzzles. I guess they don’t really care about copy-pasting as there is no ranking involved and 50 xp is not that much at these levels… I also guess they are auto-publishing these solutions and there might be a few more people doing the same silently.
Anyway this can only be done by level 29+ people – most of them certainly don’t do it – and I don’t think it’s a huge concern for CG (puzzles are in the Practice section after all).

If you’re worried about plagiarism, then take a look at this, or this

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After the recent changes to rewarding points by approving/disapproving submissions, it seems people are getting harder to create “free” points easily, so induced some people to cheat points by stealing codes, in a large scale, programmatically.

One day it will become possible to type in a puzzle name + “solution” in google to discover my own code. That will seriously discourage contribution. According to the license term I agreed to allow my contribution to be published, but that should not include my testing solution also be published transparently.

CG have a reason to block this loophole before permanent damage is done.

I don’t think this is a big harm.

Farming XP with puzzle moderation was harmful because it means very bad puzzles for CodinGame.

Farming XP by copy/pasting a solution means just a bigger level for someone. But since this codingamer is already a moderator, a higher level means nothing. And no one care about the level.

“Reputation” is the keyword, the reason for CG to fix loopholes.

Would CG like to see that:

More training classes or U courses use CG puzzles/games as assignments, so that students get to know the name of CG and when they graduate and to seek a job they will remember CG?

At the same time more serious members or recruiters will be willing to contribute high quality puzzles/games to CG as their training materials, and also enhances CG’s repository quality?

More and more job seekers write in their resume: “Obtained Level XX in CG, username as XX, with such and such accomplishment…” with some proofs, and more and more employers recognize CG accomplishment is a good indicator of a candidate’s IT skill as well as social skill, teaming skill, leading skill, mentorship skill, documentation skill, etc?

Congrets to CG, these trends were starting to grow in the last year.

But if CG allows or passively encourage cheating, it washes its own reputation away. Mentioning an untruthful CG in resume? Do you think anyone would do it any more?

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If a company take a CG account level as a proof of skill, well, i just hope i’ll never works for this company.

You can cheat your level in many ways. Just by copy/pasting solutions on github for every official solo puzzles. According to some people, you can reach top 20 (legend league) in every official multiplayer puzzles by copy/pasting a solution in the first page of google (i never tried, but just looking at some puzzle, i found a working solution of the top 3 contest, so i suppose it can reach top 20 on the multiplayer puzzle easily).

So yes, a moderator can have free XP by copy/pasting contribution solutions. But this is clearly not the worst issue with the XP system.

We can argue that this is bad for codingame reputation. But so it is for HackerRank since a top ranked just wrote an article of how he just googled every exercices.

Agree to it very much. CG achievement is something not worth mentioning - because CG’s reputation is too low? Wondering why CG feels no pain about this comment, and have no desire to fix it.

Achievement on record is just a starting point to catch the eyes of recruiters, a handle for candidates to “lead” the recruiters to talk more about certain topics. If done well, it can give additional impression scores besides the regular interviewing and coding tests.

hello all, and thank you @java_coffee_cup for bringing up this issue.

tl, dr: I don’t see it as a big issue. It’s part of a bigger question of how we handle the XP system vs the solution system. I’ll work on it.

Let’s look into this calmly.

Some CodinGame members seem indeed to have used the solutions of authors in community puzzles and published them (either automatically or intentionally).

I don’t like so much to assume people’s intentions but I’d say these members do it for two main reasons:

  • break or win “the game” just because it’s possible
  • boost their profile for personal ego or a recruitment process

I’m sure some players also use the solutions to learn from the authors or just pass a puzzle they blocked on. Anyway, let’s look at the impact it has for…

  • the other players: a feeling of injustice perhaps for those who are aware of it and care about it (some players do @Magus ). However, there is no competition about the level on CodinGame, there is not even a XP-based leaderboard, it’s mainly for personal motivation. I suggest checking out this nice blog article/slideshare about gamification
  • the authors: maybe the biggest issue here. While they indeed agreed to share their solution while publishing the contribution, it’s not cool to see them also published by others next to theirs.
  • CodinGame. If recruiters trust the CG profile as they would trust a resume, they’re just bad recruiters. Also, CodinGame is not a tool for recruiters to evaluate developers’ skills, CodinGame for Work, our assessment platform, is. (We have an anti-cheat system there)

I agree that the solutions system on CodinGame has many flaws. I also think that by choosing to hide solutions to most players, we underestimate the value of knowledge-sharing and how helpful it could be for a lot of people. I’ve been thinking about this for a while and it could be interesting to improve the solutions system this year or next year.


There’s no need to submit it to learn. Reading it is enough.


However, there is no competition about the level on CodinGame, there is not even a XP-based leaderboard, it’s mainly for personal motivation.

Well, there is an unofficial one at https://chadok.info/codingame/leaderboard_xp.html which I regularly check (but yes, mainly for ‘personal motivation’ :slight_smile: ) But I agree, that XP is much more about sedulity (or how much time you invest) while CP is much more about coding excellence. (No matter how much time I would invest, I don’t think I could get into Top3 in any multi, while I think I could do almost all solo puzzles (well, at least I did 80% in one year already, and not with the copy paste method…))

Note: even if it is an XP leaderboard, you are left out if you never did it to the CP Top1000. But without touching the multiplayer games, there is a hard XP limit around Level 39-40 (or 40k XP), so the XP leaderboard is more or less accurate. Notably missing: @java_coffee_cup :slight_smile:

@java_coffee_cup, what do you propose CG to do, concretely?

What I could think of have already been under consideration by Thibaud. I do not have further concrete suggestions. But anyone is free to provide ideas.

Thibaud promised an action and a rough timeline. The community got alerted of this issue and have a chance to discuss it. These have fulfilled my expectation. Thibaud knows the playground best. It is his mission to balance the players interest and the CG’s interest. I’d trust on him.

Though said I do have not many concrete suggestions, there are still some:

“Copy-and-paste experts” know how to hide evidence of their acts. But it cannot hide staff’s monitoring.

CG can make bots to scan players’ first successful submission to a puzzle, to check against the author’s solution. High similarity should raise alert for human check.

There are plenty of algorithms for text similarity comparison and are not too hard to implement. I do not need to go into details here.

Another bot scanning is abnormal frequency and intensity of submission. There is the gotcha machine for CoC. I guess it is also covering puzzles/games but the config should be different.

In somewhere in FAQ or Rules, CG should explicitly state its policy and attitude towards “code theft” acts.

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For a very easy puzzle, the first succesful submission of everyone will be pretty much the same as the author solution (if they use the same langage, of course).

I trust CG developers know how to set a reasonable boundary in different cases. The detection result does not need to cause immediate reaction, but should alert staff to review. When they got too much false-alarm they know how to adjust it again.
Besides, for a player to accumulate enough xp to become moderator, he should have already passed most easy puzzles by his own work. Perhaps not much to farm in Easy or onboarding area.

But you assume CodinGame will spend time for that. Checking alarm (false or not), compare with the author solution, compare with other published solutions. What if someone just gives his own code to a friend ? That’s also cheating.

I don’t see how CodinGame can detect all the case, sit down, analyse the situation and do something (if there’s something to do). And i don’t think CodinGame will pay someone for that but i can be wrong.

In my opinion, a better solution already used on CodinGame is the auto-moderation by the community itself. Just add a report option on published solutions and take an automatic action with enough reports. But this solution won’t prevent cheater to just solve a puzzle and never publish their code.