fwm94's blog

Code leaked in round 446
By fwm94, history, 7 years ago, In English

I participated round 446, after system test, system tell me my 32403500 coincide with 32404737. The code is surprisingly similar, however I can prove it was written by me. When I see 891C - Envy, I remember a similar one 160D - Edges in MST, so I refer to my own solution 4398082. It is easy to see that 32403500 and 4398082 are quite similar at some parts of the code, especially in the beginning of the code and in the beginning of the main. Some variable defined in 32403500 is unused, because they just come from 4398082.

Please explain how to get my code:)--Jones.Polynomial1

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

If you didn't compile it on some public site like ideone then isn't it possible that Jones.Polynomial1 also recognized that the problem was similar to 160D and went looking for accepted code? And maybe he keeps you as a friend to read some of your solutions and then he saw that you solved it so he figured he could just copy and paste most of your solution.

Sounds a little far-fetched but it seems a little weird that he'd go for your code specifically to copy and paste.

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    7 years ago, # ^ |
    ← Rev. 2   Vote: I like it +27 Vote: I do not like it

    Come on, is it some sort of sarcasm from your side, or you didn't check submissions mentioned?

    I wouldn't expect such an exact implementation match even for two guys who spend a few years in same ICPC team :) To give you the idea: here is the diff of that "accidental match": diff. And here is the diff between updated code and code from old problem: diff.

    Upd. OK, now I've read your response below, thanks for clarifying what you meant.

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      7 years ago, # ^ |
        Vote: I like it +16 Vote: I do not like it

      I think you misunderstood me. Jones.Polynomial1 definitely copied fwm94's code I was just explaining why/how Jones.Polynomial1 got his code specifically. Sucks that he wouldn't just take the time to understand the solution and code his own version.

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      7 years ago, # ^ |
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      OMG! He actually did all that work himself!! Putting braces and parenthesis, changing lower case to upper case... so much hard work

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7 years ago, # |
  Vote: I like it +18 Vote: I do not like it

Where do you write and compile your code during contests?

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    7 years ago, # ^ |
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    Code is written and compiled in my computer.

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7 years ago, # |
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I have the same experience this round. system tells me that:" Attention! Your solution 32386503 for the problem 891D significantly coincides with solutions -horizon-/32386503, best.code/32390666. 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." but actually I never know this person before and I didn't do anything except solving problems alone I am sure that I know nothing about this event Please explain how to get my code too best.code

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    7 years ago, # ^ |
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    I notice that I_love_Tanya_Romanova is also copied by best.code

    I think this can also prove that I_love_Tanya_Romanova and I is innocence and best.code should take all the responsibilities .

    I hope I_love_Tanya_Romanova's and my rank and rating could be back

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      7 years ago, # ^ |
      ← Rev. 2   Vote: I like it +40 Vote: I do not like it

      Strictly speaking, it doesn't really prove anything — one can say that maybe we both used Ideone and don't want to admit our mistakes :)

      I don't care about rating, I care little about having the contest rated for me — maybe to have the fact that I participated being logged in my stats since at CF list of the contests only displays rated events — but it's not a big deal either; however, I don't like the situation itself. I don't know if so many people were affected by something similar in recent rounds — you don't notice it unless it affects you :) But this time I see at least 5 people complaining, and I believe that most (if not all) of them actually didn't make any stupid stuff like intentionally cheating or using Ideone for testing their code. I've already read about "lock and steal code" vulnerability, but I don't know if it was the main issue here — once again, I checked problem C in my room and none of the contestants locked it. I don't really enjoy the idea of being afraid that somebody hacked my account, or the idea that somebody can make the round unrated for me just because he doesn't like me or because he finds it funny :)

      And in case there is vulnerability which allows stealing literally any code by any contestant — of course I don't like it at all, because it can damage fair play a lot, in case it is getting used by somebody smart enough to at least re-write solution by himself instead of copy&paste.

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        7 years ago, # ^ |
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        Are we positive that locking the problem only gives you access to solutions in your own room? I'm pretty sure (not certain though) it affects seeing the code of other participans immediately after the contest.

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7 years ago, # |
  Vote: I like it +24 Vote: I do not like it

I do not know what is going on! I have not logged in codeoforces for nearly two months until now. Obviously,It must be there was a malicious guys hacked my account and cheated in round 446.[submission:http://codeforces.net/contest/891/submission/32495670]I do not know how he stole my account.Maybe he know my password so he could logged in my account? This will not happen again,I updated a new password just now.

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    7 years ago, # ^ |
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    Updating password on an HTTP-only website is only a slightly useful measure.

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    7 years ago, # ^ |
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    Does it mean that codeforces is not safe? Actually, some time ago I'd seen a blog about hacking CF accounts using Codeforces API but unfortunately, nobody answered it. Maybe it is a right time to have a look into this issue MikeMirzayanov?

    IMO, for every platform safety of their users should be the main thing that they need to focus on.

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    7 years ago, # ^ |
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    Why don't you use a gmail account for logging? Remote logins are notified on the spot.

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    7 years ago, # ^ |
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    Something weird happened with me a few months ago too. I logged in (with my infos) on my PC and I found myself in some other account. but logging out and logging in again fixed the problem.

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    7 years ago, # ^ |
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    WOW! See this submission also: http://codeforces.net/contest/888/submission/32379786

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7 years ago, # |
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Are you guys using some additional plugins either to test your codes locally or submit them directly by some browser extension. This can be one of the causes that someone is able to peek at your code.

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