Kareem_Elgoker's blog

Plagiarism (Skiped solution) Mistake
By Kareem_Elgoker, history, 4 months ago, In English

I've got this message in the morning this day :

Attention!

Your solution 274855834 for the problem 1999F significantly coincides with solutions Kareem_Elgoker/274855834, Eyad_Abd_El-Mohsen/274908131. Such a coincidence is a clear rules violation. Note that unintentional leakage is also a violation. For example, do not use ideone.com with the default settings (public access to your code). 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. More information can be found at http://codeforces.net/blog/entry/8790. Such violation of the rules may be the reason for blocking your account or other penalties. In case of repeated violations, your account may be blocked.

My code : 274855834 His code : 274908131

We have used a pre-published combinatorics template from Usaco : the link for the template, you can find the template code after -> Method 2: Factorial Definition (Modular Inverses) — $$$\mathcal{O}(n + \log MOD)$$$

Also there is a proof that I don't cheat in this problem

I made a screencast for this contest and had uploaded it on youtube : https://youtu.be/whG44e-HVuc?si=e0kzzTJ_AvgphR10

SlavicG, flamestorm, mesanu, MikeMirzayanov

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4 months ago, # |
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Support.

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4 months ago, # |
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Agreed!

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4 months ago, # |
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Support

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4 months ago, # |
  Vote: I like it -39 Vote: I do not like it

Codeforces has been floccinaucinihilipilification

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    4 months ago, # ^ |
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    Can't be more accurate!!

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4 months ago, # |
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this is why you should make your own templates...

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    4 months ago, # ^ |
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    Tell'em

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    4 months ago, # ^ |
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    And what if someone uses my templates in upcoming contests??

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      4 months ago, # ^ |
      ← Rev. 2   Vote: I like it +4 Vote: I do not like it

      unless you publish your templates it's unlikely someone is just gonna look at your submissions and decide to use your templates instead of the hundreds of well-known templates already out there...

      obviously using public templates is allowed and you should report false positives in the plagiarism detection, but this way it is just more convenient and you probably won't have to deal with that.

      Plus, it feels nice to use your own code.

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        4 months ago, # ^ |
          Vote: I like it +36 Vote: I do not like it

        Actually, alot of my friends use some of my codes instead of writing templates themselves, sometimes we even study together and write a template together to use.

        Also, sometimes I reuse the same logic/code as people whom I have seen their solutions on problems I was stuck on.

        So, this really happens although its not very frequent

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    4 months ago, # ^ |
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    love u houshou marine :3

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    4 months ago, # ^ |
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    I literally spent a day to create my custom template in Java.

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    4 months ago, # ^ |
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    mol

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4 months ago, # |
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Support SlavicG

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support

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4 months ago, # |
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Support

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4 months ago, # |
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4 months ago, # |
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support :)

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Support.

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Support

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Support <3 , Maybe iam the reason.

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Support

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4 months ago, # |
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I think egyptians should stop spamming. You are defending 2 guys from the same university and they are probably friends, is it a coincidence?.

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4 months ago, # |
← Rev. 2   Vote: I like it -7 Vote: I do not like it

انا شارب تلاتة ستيلا انا راجل جامد مش قلة

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4 months ago, # |
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justice_for_Eljoker

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All support

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Support

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4 months ago, # |
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All support, kareem

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na i think ur capping

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All support

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4 months ago, # |
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I am gonna try be objective here. The plag checker can't be blamed. Templates are identical and yes, it is pre-published, but the solve() part is identical as well just very slight differences. It is an easy problem, with simple maths logic so implementations shouldn't differ a lot.

Being friends from same university (as apparent in profiles and teams) raises suspicions also, but I think the screencast is a good proof it was a coincidence.

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    4 months ago, # ^ |
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    same institute can very well lead to having same teachers, and most students adopt the implementation styles of their teachers (if the teachers do show their implementations, in my school they do (since preparing for OI)), hence they can have same implementation styles and almost same implementation for some classic algorithm or data structure.

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      4 months ago, # ^ |
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      Yes, I tried to help even by saying screencast is a good proof there hadn't been cheating.

      But it is notoriously too identical the solve() part and as stated by some comments by master and grandmaster down below, submission by the pupil was 5 minutes after the screencast ended and was highly obfuscated yet same logic, structure and implementation of the CM code.

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        4 months ago, # ^ |
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        I am sorry, but I was not being specific here.

        Spoiler

        I just wanted to convey that being at the same institute can lead to having same coding styles, that's it.

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4 months ago, # |
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Support u brother

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Support

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4 months ago, # |
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the same problem with me I don’t know why all problems is skipped ،Even though I didn't cheat.

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4 months ago, # |
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1) Your submissions are very similar even if we're not taking into account the copied template. As someone already pointed out here in the comments, solve part is practically identical. You can even kinda see who was copying whom just by looking at the code.

2) Your screencast doesn't really prove anything. Your submission was made at 18:44:47, Eyad_Abd_El-Mohsen made his at 19:26:39. Your video cuts off at approximately 19:21. Five minutes is plenty enough to change the variables' names and formatting (not even talking about how sus it is that your video cuts off this early).

Occam's razor (codeforces version): "If two dudes from the same university have very similar submissions, they probably cheated".

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    4 months ago, # ^ |
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    some one already pointed out, solve is identical

    Yes, it was me. I did not further check the screencast, but your investigation and point 2 is good. I would not oppose.

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    4 months ago, # ^ |
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    By logic this contest is unrated for me, if I want to cheat and give solutions to someone, why did I solve the problems in my account? Is it to get skiped in my highly-rated personal account?

    I could go and solve the problems with him directly in his account, if I want to make this.

    Also why he didn't take problem G2 from me ??

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لا لا لا لا لا لا لا لا لا لا لا لا جن جنون الكوري

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4 months ago, # |
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Ain't it all already fishy if you both are of same university?

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4 months ago, # |
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I find it kind of humorous how clearly obfuscated Eyad_Abd_El-Mohsen's solution is.

Weirdest way to do k-(k+1)/2 = k/2
Who uses O_O for mod

I even checked other combinatorics problems he did to see if these quirks reappear: 270191738 224800945. They don't! He uses mod for mod just like anyone else and the code isn't as weird. Not even bringing the fact that you guys are from the same uni and do contests together, I would say it is great that codeforces skipped your solutions!

Also as smalyarovsky pointed out, the screencast doesnt mean anything.

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    4 months ago, # ^ |
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    he responded to all of the stuff above but not this one , typical .

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    4 months ago, # ^ |
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    You really went the distance with this one. I, honestly, didn't even bother to look closely into the code after I noticed that the screencast is cut off.

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