Kareem_Elgoker's blog

Plagiarism (Skiped solution) Mistake
By Kareem_Elgoker, history, 2 years 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.me/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

  • Vote: I like it
  • +107
  • Vote: I do not like it

Comments Comments (38)
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2 years ago, hide # |
 
Vote: I like it -19 Vote: I do not like it

Agreed!

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2 years ago, hide # |
 
Vote: I like it -14 Vote: I do not like it

this is why you should make your own templates...

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    2 years ago, hide # ^ |
     
    Vote: I like it +39 Vote: I do not like it

    And what if someone uses my templates in upcoming contests??

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      2 years ago, hide # ^ |
      ← 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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        2 years ago, hide # ^ |
         
        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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2 years ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

Support SlavicG

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2 years ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

support

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2 years ago, hide # |
 
Vote: I like it -6 Vote: I do not like it

Support.

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2 years ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

Support

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2 years ago, hide # |
 
Vote: I like it -21 Vote: I do not like it

Support <3 , Maybe iam the reason.

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2 years ago, hide # |
 
Vote: I like it -8 Vote: I do not like it

Support

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2 years ago, hide # |
 
Vote: I like it +37 Vote: I do not like it

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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    2 years ago, hide # ^ |
     
    Vote: I like it +32 Vote: I do not like it

    Bro's from Zagazig and saying i think egyptian, WTF man

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

    Did U even compare thier codes?!!

    I am sure U didn't, cause you weren't even able to solve this ez prob XD

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    2 years ago, hide # ^ |
     
    Vote: I like it -16 Vote: I do not like it

    I think bro a 2048 rating participant can solve div 4 easily and f also was an easy problem so don't try to be honest and talk with this bad speech with Egyptian guys like u and for sure both are also better than u even in problem solving or morally

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      2 years ago, hide # ^ |
       
      Vote: I like it +17 Vote: I do not like it

      He can be a grandmaster and still a cheater, it doesn't matter

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        2 years ago, hide # ^ |
        ← Rev. 2  
        Vote: I like it -10 Vote: I do not like it

        I know this guy bro he is the head of it in mansoura university training and he is working hard and got Bronze medal in Ecpc if u think this rating is with cheating the problem is with u trust me

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          2 years ago, hide # ^ |
           
          Vote: I like it +1 Vote: I do not like it

          btw I didn't say he cheated from somewhere else, but I'm saying he gave the solution to his friend, this is also cheating.

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2 years ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

Support

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2 years ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

All support, kareem

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2 years ago, hide # |
 
Vote: I like it +7 Vote: I do not like it

na i think ur capping

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2 years ago, hide # |
← Rev. 3  
Vote: I like it +80 Vote: I do not like it

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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    2 years ago, hide # ^ |
     
    Vote: I like it +19 Vote: I do not like it

    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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      2 years ago, hide # ^ |
      ← Rev. 2  
      Vote: I like it +17 Vote: I do not like it

      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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        2 years ago, hide # ^ |
         
        Vote: I like it +13 Vote: I do not like it

        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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2 years ago, hide # |
← Rev. 2  
Vote: I like it +96 Vote: I do not like it

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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    2 years ago, hide # ^ |
     
    Vote: I like it +9 Vote: I do not like it

    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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    2 years ago, hide # ^ |
    ← Rev. 2  
    Vote: I like it -15 Vote: I do not like it

    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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2 years ago, hide # |
 
Vote: I like it +1 Vote: I do not like it

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

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2 years ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

Support

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2 years ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

Ain't it all already fishy if you both are of same university?

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2 years ago, hide # |
 
Vote: I like it +103 Vote: I do not like it

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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