EMBailey's blog

Probable Cheating
By EMBailey, history, 3 years ago, In English

After briefly looking through the scoreboard for Codeforces Round 764 (Div. 3), which is still in the hacking phase as of when I posted this, I noticed what appears to be cheating. All users shown in the first screenshot, with the exception of those in the top and bottom row, have exactly the same submission time for every problem. Additionally, the submissions of theirs I looked at are filled with comments and macros that appear to be random in an attempt to avoid the Codeforces cheat detection system (an example of which is shown in the second screenshot).

As an aside, is there a better way to handle such issues than cluttering the recent actions bar with a blog post? Thanks in advance.

EDIT: Here's the URL of the standings page in question (make sure "show unofficial" is checked): https://codeforces.net/contest/1624/standings/page/2

EDIT 2: This has since happened in other contests; see the comments for details.

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3 years ago, # |
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Auto comment: topic has been updated by EMBailey (previous revision, new revision, compare).

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3 years ago, # |
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Auto comment: topic has been updated by EMBailey (previous revision, new revision, compare).

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3 years ago, # |
  Vote: I like it -37 Vote: I do not like it

Very impressive sir ILL1A

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3 years ago, # |
  Vote: I like it +58 Vote: I do not like it

Something similar also happened. As a side note, considering how this is quite obviously smurfing and is also easily detectable, it seems that this is vandalism more than anything.

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3 years ago, # |
← Rev. 2   Vote: I like it +77 Vote: I do not like it
Meme:
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3 years ago, # |
  Vote: I like it +44 Vote: I do not like it

There should be verification for email change in settings. One can change it to anything once registered and create any number of accounts using the same email id.

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3 years ago, # |
  Vote: I like it +23 Vote: I do not like it

Be confident, delete the Probable

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3 years ago, # |
  Vote: I like it +40 Vote: I do not like it

I don’t understand why this is done at all, can someone explain to me? there are not any prizes or money that would be given to you if you won. why not just say thank you for organizing such a competition and not interfere with the development of the system? apparently someone does not care about the work of others. and this is very sadly.

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    3 years ago, # ^ |
      Vote: I like it -44 Vote: I do not like it

    thanks for organizing!

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      3 years ago, # ^ |
        Vote: I like it +5 Vote: I do not like it

      As a cheater, you have the guts to show up here, wow. Well, it's good that all of your submissions were skipped.

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    3 years ago, # ^ |
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    as a theory, they do that to earn more money at crowdforces.

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3 years ago, # |
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This qurobastuc is one cheater that can not be deterred. He is still doing the same thing in round 765 div2. Look at his submissions.

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3 years ago, # |
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Looks like it happened again on Codeforces Round 766 (Div. 2). It was not just qurobastuc and porgulyto this time though; by scrolling down on the standings page, you can see all of the same accounts from the original blog post with slightly different submission times. In particular, I was also able to find laplasor, loverbar, jdklove, golovster, tysbekai, kolovalir, memkaol, mochito, rumbasal, abrokosy, pofagolo, hubabubas, loborotu, hurobatigo, lapgoratiro, torylius, and miagiro, although I would not be surprised if there are others. The comments are different this time (they consist of random nonsense C++-ish code), which seems to have enabled them to evade the cheat detection system for nearly a week.

If anyone on the Codeforces team reads this, would you consider preprocessing code before running cheat detection software on it to mitigate this sort of thing? Removing comments and macros for tokens that are not used later seems like it would be fairly straightforward.

Standings page: https://codeforces.net/contest/1627/standings/page/3

Example submission: 142836348

Screenshot
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    3 years ago, # ^ |
      Vote: I like it +7 Vote: I do not like it

    Not sure if the codeforces admin is monitoring this, but I guess this has been an on-going struggle. It'd be better if these is a report function here, so every one can report cheaters. But then again verifying all the reports can become time-consuming for the admin.

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