Whimpers's blog

By Whimpers, history, 4 months ago, In English

Hi MikeMirzayanov.

I believe many people have cheated in the most recent contest, this behavior should be unacceptable. It also appears there are groups of people helping each other cheat.

Take note of the comments in this submission: 174424727.

// if a[i][l]==a[j][l] then d+=a[i][l] else d+=3-a[i][l]-a[j][l] //this is the line that I don't know how to translate into cpp. I tried to use ternary operator but it doesn't work. Please help me! Thank you!

// return 0 in python is return 0 in cpp? I'm not sure about this one too! Please help me! Thank you! :)</code>

It is clear that this person is cheating.

I believe this has significantly effected the ratings of competitors, including me, in this most recent contest. I would put heavy suspicion on all long-standing newbies who have recently skyrocketed to the top 1500 in this contest. It is almost assured that they are cheating. You can notice the unusual spike in the rating graph of the user whose submission I have linked.

I have also found that all of these submissions are exactly the same. There are more, I will find them later: 174418316 174422837 174422837 174422426 174428235 174428573 174413648 174424155 174427490 174422837 174413565

Thank you for your time.

 
 
 
 
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4 months ago, # |
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This needs to be stopped, it is ruining the integrity of the contests. It ruins not only my experience, but also the experience of others.

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4 months ago, # |
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To the HQ: Would it be possible to implement a relatively weak (but relevant) "duck test" in the plagiarism checker? The comments are not the only suspicious thing in the code, also the indents are broken here and there. Most of the time the participant would be using one environment for a contest, so the indents and codestyle would be mostly consistent throughout a contest (and many times across multiple contests as well). Therefore detecting inconsistencies in the codestyle would help find suspicious code.

p.s. Please note that "weak" in this context does not mean "powerless", it means "not forceful" as duck tests can cause false positives

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    4 months ago, # ^ |
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    Why so many downvotes? I think my comment has a clear point (on implementing a duck test in the cheating detection).

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      4 months ago, # ^ |
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      coding styles does change from time to time if you're new, i know it because the piece of codes i write now and a month ago are very different, this cannot be an accurate measurement

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        4 months ago, # ^ |
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        Agree on that, but the codestyle within one contest would be consistent most of the time. The cheater's code provided had a whole block with a broken indent layer. Of course I know this can cause false positives, hence the term "relatively weak". Different methods of checking (i.e. manual check) can be used for these kinds of suspicion.

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          4 months ago, # ^ |
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          that is true, this can be applied to more complex problems where you need implementations, very rarely does 2 people has the same idea and same way of implementing something

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          4 months ago, # ^ |
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          I've seen at least a few reds who used tabs while writing library code (or just took some stuff from someone else's old submission) but used spaces in the remaining code. Also, this gives a false positive if someone doesn't have time to format their code before submission (for instance, realizing just before submitting that there are multiple tests in the same input file).

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            4 months ago, # ^ |
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            that's fair, we need human reviewers either way

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4 months ago, # |
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LMFAO THE CLEAR PROOF LOL

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4 months ago, # |
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Auto comment: topic has been updated by Whimpers (previous revision, new revision, compare).

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4 months ago, # |
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Okay, I checked other submissions of his in the same contest, and found lines in other problems' submissions with variables with a very certain same name (g_of_sum, additional_value_sum). Now I think he intentionally tried to fool the detection.

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4 months ago, # |
Rev. 6   Vote: I like it +22 Vote: I do not like it

Hi guys, I also tried to find out and concluded by three factors-

1) This blog.

2) By Poremax738

3) Watching most of the users who submitted in Python and a few in C++.

This code was leaked for problem C
This code was leaked for problem D

Due to this solution leak, the ranking of many users(including me) was seriously affected and lowered considerably.

MikeMirzayanov I know it's a big task but please personally look at the solutions of C and D, especially from those who performed exceptionally good in this contest.

Happy Coding!

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4 months ago, # |
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Not only D was leaked last contest, But also C! Leaderboards are so messed for the last contest, cheaters doing both C and D was shit See Similar Submissions for C below,

174427324 174419555 174427324 174421050 174415745 174418707 Those are just few.

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4 months ago, # |
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why so many cheaters,fuck them.

I never cheat though I lose my rating.