adnan_toky's blog

By adnan_toky, 8 months ago, In English

In the last round, I have received two unexpected warnings from CodeForces plagiarism checker. The first one says, my solution 105930169 for the problem 1476D - Journey significantly coincides with solutions bleh0.5/105914875. After sometimes I got another warning that my solution to the same problem (1476D) significantly coincides with solutions bleh0.5/105914875, tejas10p/105917332.

My approach for problem D was quite straight forward. Just three operations in three different loops. Whoever solved the problem using this idea, it is quite possible to match their solutions. I have explored the submissions of the first 100 people according to the common standings of this round. Among these 100 submissions, I found 7 submissions that are also quite similar to my solution. It does not mean that we all shared our code among us, it is just that our approaches were same. I'm mentioning these 7 submissions here.

My submission:

The two submissions that matched with my submission:

Similar submissions:

  • 105883915 — Here only difference with my solution is I used array and he used vector.
  • 105878527 — He used vector and wrote the solution in a separate function.

Other similar submissions:

I already commented on the post but nothing changed. So I am here annoying you again. From the day (16 Feb, 2020) I did my first contest here, i never missed a single round regardless of how busy i was. I love my cf profile more than anything and just can't let a scar stay on my profile without any wrongdoing. -_-

I am requesting MikeMirzayanov & awoo to look into these unexpected warnings.

 
 
 
 
  • Vote: I like it
  • +61
  • Vote: I do not like it

»
8 months ago, # |
  Vote: I like it +5 Vote: I do not like it

It's also strange that your submission was skipped but the other guy's submission was accepted O_o

»
8 months ago, # |
  Vote: I like it +14 Vote: I do not like it

This is so unfortunate.

I have seen similar false positives for easier problems where implementation is so simple that plagiarism checker thinks all solutions are plagiarized even if nothing like that happened. The submissions here look like similarly victimized.

I am hoping CF team will kindly check out this issue and take the necessary steps. Best of luck.

  • »
    »
    8 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    i just have one doubt..(i know how compilation takes place , first the pre-processor processes the code and replace the statements using the macros. )

    But the thing is even if the online judge had checked the entire code for plagiarism and not the compiled code(assuming it from your skips) , then your would have passed.

»
8 months ago, # |
  Vote: I like it +22 Vote: I do not like it

MikeMirzayanov, please give some attention in this and look into the matter.

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

It's really heartbreaking when you find a short and easy approach for a problem and get "skipped" for that as well.. :|

Not expected from CodeForces.. -_-

»
7 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Shouldn't be there a manual check on those solutions that got matched by the 'CF plagiarism checker'? This false positive on plag-detection is happening a lot these days. Specifically, in easier problems.

Kicking someone out of a contest without any further verification is a serious thing. We love competitive programming thus our CF profile. Getting a plag-scar without doing anything wrong might hurt the motivation behind all of this.

Please look into this matter, MikeMirzayanov!