kira201's blog

How good is Codeforces Plagiarism Checker ?
By kira201, history, 3 years ago, In English

In the codeforces round 709, I made a submission from my alt account for div2A to see if the codeforces plagiarism checker really works. To be honest, I thought initially that the round was unrated because of no formal announcement, so I dared to try it out. Eventually, ended up losing rating ,lol. Well, it doesn't matter.

Here are the two submissions:110629586 and 110636692 with exact 100% match. But, the plagiarism wasn't detected. So, I wondered if several such submissions go unnoticed every contest to due to this bug or am I missing something. Feel free to comment, I don't care about the downvotes as well but if this is a serious issue, MikeMirzayanov please look into it.

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3 years ago, # |
  Vote: I like it +18 Vote: I do not like it

My guess is the plagiarism checker won't be run on all the questions in a contest because it is highly likely that one solution to trivial problems (implementation wise) such as the one that you have shared is similar to another.

PS: I don't think having an alt account is a good idea. Not sure about the exact rules though.

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    3 years ago, # ^ |
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    Yeah, I understand in many cases div2A and B are trivial, so the logic can be same. But what about the case when there is a 100% code match as above, like those who copy and paste the solution received from their friends or groups.

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3 years ago, # |
  Vote: I like it +22 Vote: I do not like it

It is not exactly the same code, because one uses "GNU C++17" compiler and the other uses "GNU C++17 (64)", so when the compiler replaces the libraries, maybe it will produce a different code, but yeah, definitely the Code Plagiarism Checker should detect this kind of things.

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3 years ago, # |
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I got plagiarized for the first question. My sol — 109233079, Other sol — 109231770 So, imo plag checker runs on every problem even if sol is very trivial

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3 years ago, # |
  Vote: I like it +70 Vote: I do not like it

Sure, if a problem is like print a*b we don't run anti-plagiarism. And the fact that the codes coincide can only mean that the participants use the same template code. It is strange to punish for this.

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    8 months ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    MikeMirzayanov Is plagiarism checking still done on Codeforces? I was checking it for some of the recent contests and did not find any skipped solutions.

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3 years ago, # |
  Vote: I like it +3 Vote: I do not like it

At what percentage are the two solutions plagarized?

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9 months ago, # |
  Vote: I like it -19 Vote: I do not like it

How much rating did you lost ? kira201

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    9 months ago, # ^ |
    ← Rev. 2   Vote: I like it +3 Vote: I do not like it

    Bro looking at your contest history and contest submissions it's clear to see why you're asking this question lol.

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      9 months ago, # ^ |
        Vote: I like it -19 Vote: I do not like it

      Your profile looks very suspicious

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        9 months ago, # ^ |
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        How lol?

        Also says the guy whose all submissions of last div 4 were skipped and who uses his name for defining variables and macros and uses pretty shady variable names in literally all his submissions. C'mon bro what's the use of the rating if you gain it by cheating?

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9 months ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

I think plagiarism is only detected when there's a similarity between two problems, not just one, and plagiarism is still run on trivial problems.

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8 months ago, # |
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I think it depends on the compiler as the code changes when there is any change in compilers.

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