kdrkdr's blog

By kdrkdr, 5 weeks ago, In English

On the recent round 750 (div. 2), I originally got placed around 400th place solving ABCDF1, and have passed all systest. However, I then got a message from a friend saying that my submissions have been skipped. Logging onto CF, I was greeted with this message

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I was very surprised at first. However, after checking our code, it did turn out to be very similar in term of solution. While this may be very suspicious, this could very well happen on complete accident. In my case, I claim it was complete coincidence, as the solution to the problem was very simple and short.

I then appealed on the aforementioned blog attached within the message. Nothing came back. Not even a verdict. Now at this point I was quite angry, because I would not think this is how a platform would want to treat its users, even if I was not legit.

Looking around my comment entry, I realized there was a few other people who have also been wrongly flagged. for example, this guy who is right under me in the comment section of the blog.

Such neglect really demotivates the minority who have been unfortunately flagged by the Codeforces anti-cheat. While there are no perfect solution to this problem, I think the staff of Codeforces or whoever is in power should at least quickly go through some of the appeals, especially people who have solved a decent amount of problem during that contest / have decent performance, so that their effort doesn't go in vain, or at least give a closure to them.

Whatever happens, I am going to continue to do codeforces problems and contests, but I am very bummed out by this.

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5 weeks ago, # |
Rev. 2   Vote: I like it -37 Vote: I do not like it

hi

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5 weeks ago, # |
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Bro, chill and just try not to cheat next time. Being deceitful might secure some short-term benefits for you, but it’s not the way to the true success. Trust me, I’m a Candidate Master after all.

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    5 weeks ago, # ^ |
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    I know the author of this blog in real life and I can guarantee that he did not cheat and won't ever cheat in a codeforces round.

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    5 weeks ago, # ^ |
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    Bro, chill and just try not to accuse others next time. Being vindictive might secure some short-term benefits for you, but it’s not the way to the true success. Trust me, I’m a Grandmaster after all.

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      5 weeks ago, # ^ |
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      Pretty ironic how you used plagiarized text to defend a plagiarist. Are you guys from the same Canadian League Of Plagiarism or something??

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        5 weeks ago, # ^ |
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        yes. how else do i get rating?

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        5 weeks ago, # ^ |
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        Let me just put out some points here:

        a) There wasn't a need for you to accuse him for cheating in the first place. Clearly this is an issue between the admins and the people involved, and it benefits no one for you to go tell him to try not to do something he potentially never did in the first place.

        b) If you're not aware, the world isn't perfect, and neither is the plagiarism checker. If you look at the system message screenshot, even that takes into consideration of the fact that it could be a coincidence; so your accusations are pretty much baseless.

        c) Regarding the "plagiarized" text, you wouldn't have been convinced by the comment either way (or you would have just ignored it), so it was probably more of a way to grab your attention. However, it seems like it only added fuel to the fire because not only were you not convinced, you decided to make up some nonexistent national league just because they were both from the same country, which is not really okay.

        Overall message: just don't be that person...

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          5 weeks ago, # ^ |
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          just because they were both from the same country

          I mean... you are from the same country too. Funny how this thread became full of angry Canadians harassing me for nothing.

          Have you guys ever heard about pluralism of opinions and freedom of speech?

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            5 weeks ago, # ^ |
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            Go back lifting bro, that seems to be the right place for you. Why bother being here if you solve less than 6 problems a year anyway?

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            5 weeks ago, # ^ |
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            cock lmao

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        5 weeks ago, # ^ |
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        Imagine hitting Candidate Master before Master. Pathetic.

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        5 weeks ago, # ^ |
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        Unsure if you're ignorant, stupid, or both.

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          5 weeks ago, # ^ |
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          You're such a cyberbully!

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            5 weeks ago, # ^ |
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            A cyberbully shouts to catch cyberbully. So ridiculous.

            I suggest you close your filthy mouth and reflect on it.

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          5 weeks ago, # ^ |
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          I mean, this guy posted a blog threatening to sabotage Codeforces if his friend with a highly questionable account name and highly questionable actions is not unbanned, so this kind of behavior is expectable.

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            5 weeks ago, # ^ |
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            Oh god, how the heck hasn't he been banned yet?

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              5 weeks ago, # ^ |
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              Considering Eva wasn't banned until his warning count reach the second digit, I would say Codeforces can have some pretty loose (and sometimes a bit random) regulations.

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    5 weeks ago, # ^ |
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    seeing from his account he regularly gets a rank within the top 500 so i don't think it's likely he "cheated" to stay in the same range :)

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    5 weeks ago, # ^ |
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    Plagiarism checkers often give false positives Eg:- see tourist submissions you can find skipped submissions which don't mean that he had cheated.

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      5 weeks ago, # ^ |
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      It's not necessary that the solution is skipped only when it coincides. Solutions are also skipped when you give 2 or more submissions which passes the pretest the earlier one gets skipped. Many times people give 2 submissions if they find some case where they think their code will fail so to avoid FST. And many times it happens due to lag on site.

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5 weeks ago, # |
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I then appealed on the aforementioned blog attached within the message. Nothing came back. Not even a verdict. Now at this point I was quite angry, because I would not think this is how a platform would want to treat its users, even if I was not legit.

The most important part of the message was "If you have conclusive evidence that a coincidence has occurred due to the use of a common source published before the competition, write a comment to post about the round with all the details". But this was not your case, so technically you were not supposed to appeal and there's no need to be angry because of not receiving a personalized response from codeforces.

There is always a small chance of getting a false positive with any automated plagiarism checker. Participating in many contests and solving many problems increases the probability of encountering a false positive sooner or later. Not much can be done about this. Have a look at another blog post here: https://codeforces.cc/blog/entry/93405

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    5 weeks ago, # ^ |
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    There is something that can be done. Disabling the plagiarism checker on trivial problems. Compare his submission with the editorial one. If the author of the problem wrote it in c++, I wouldn't be surprised if it got flagged as plagiarism.

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      5 weeks ago, # ^ |
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      How can we know that some reasonably effective countermeasures are not already implemented? The problem D had been successfully solved by 1973 participants. Many of them used C++. But the OP's solution was found to be coinciding with only one other submission. If the plagiarism checker was as primitive as you think it is, then wouldn't we expect to see a lot more false positives?

      As for completely disabling the plagiarism checker for trivial problems. Wouldn't this make real plagiarists very happy? Most of the cheating activity seems to be happening among beginners and turning a blind eye to them may be not the best idea.

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        5 weeks ago, # ^ |
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        Personally, I don't care if greys and greens cheat for A and B.

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          5 weeks ago, # ^ |
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          This was problem D, not A or B. It sets a really bad precedent for the competitive integrity of codeforces in general if cheating is not caught/punished for a specific group of people.

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            5 weeks ago, # ^ |
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            Most of the real cheating happens on A and B, source: see 95% of the cf blogs on it posted. I would rather allow cheaters to get their cheated A and B than honest people being punished for false positives (and CF staff ignoring appeals).

            Edit: You are right this is a D. And this was an honest person which supports my case that its mostly cheaters aiming for A and B.

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        5 weeks ago, # ^ |
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        Not sure what your view on this problem is, but I would rather miss 10 cheaters than flag one honest person as a cheater. Also: "But the OP's solution was found to be coinciding with only one other submission. If the plagiarism checker was as primitive as you think it is, then wouldn't we expect to see a lot more false positives?", doesn't really make sense. There might be many pairs of honest people who had similar submissions and got skipped.

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    5 weeks ago, # ^ |
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    Yea I get that any automated system, and even manual system for anti-plagiarism can have wrong verdicts, but I am more mad that the staff did not review any of the appeals than anything (or maybe they did, but didn't give any verdict), especially for such problems with such trivial implementation.

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Cheater getting caught and then making dramatic sob story, typical.

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"ok im mad, im gonna go write a blog", time 420