Dawnq's blog

There are big issues with CF's anti-cheat system
By Dawnq, history, 13 months ago, In English

In Codeforces Round 911, the submission 234462484 of my friend Chengxixi and the submissions of two strangers 234478413 234459397 are considered similar by the anti-cheat system. My friend really doesn't know who them are. As a coder, I think there are obvious differences among these codes. Should she be considered as a cheater in this contest?

  • Vote: I like it
  • +54
  • Vote: I do not like it

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13 months ago, # |
  Vote: I like it +41 Vote: I do not like it

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13 months ago, # |
  Vote: I like it +40 Vote: I do not like it

I have the same issue in the contest Div. 2 910 and I'm still being considered as a cheater, although I'm not a cheater. I tried to complain, but no answer at all. So I think they won't respond as well in this case. I'm wondering how should one code in C++ in order to avoid such mistakes?

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    13 months ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    There have been plag tests lately but, there's been a huge delay in rolling back the ratings of those caught cheating.Moreover. there is no proper system to report about cheating or review a false plag.

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    13 months ago, # ^ |
      Vote: I like it +11 Vote: I do not like it

    Sorry, it also was a mistake. Punishment will also be revoked.

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

There $$$> 10^8$$$ pairs of contestants in each contest, so I think it's okay if there are about $$$10^1$$$ false positive results.

UPD: steadily approaching $$$10^9$$$ pairs of contestants, insane.

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    13 months ago, # ^ |
      Vote: I like it +60 Vote: I do not like it

    Although these mistakes with a small probability is acceptable to the public, it can be very frustrating to a participant who thinks hard and codes carefully to be considered as a cheater.

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      13 months ago, # ^ |
        Vote: I like it -7 Vote: I do not like it

      That's true, but you can't get 100% accuracy anyway. That's how life works :D

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        13 months ago, # ^ |
          Vote: I like it +1 Vote: I do not like it

        That's for sure. But the algorithm can be better so that the probability can be lower. However, we shouldn't feel discouraged if it happens to us but accept it as a joke which life plays on you.

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

      You can appeal it.

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    13 months ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    hope this comment doesn't change even if it happens to you

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13 months ago, # |
  Vote: I like it +21 Vote: I do not like it

We apologize, this coincidence of solutions was indeed mistakenly perceived as cheating. The punishment will soon be revoked.

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