protalk's blog

Well... System just gave me surprising message and I have some claim of it.
By protalk, 6 years ago, In English

I got message from my friend that my submission is unrated for previous round. And then I found that system gave me some surprises.

Attention! __ Your solution 43138461 for the problem 1051D significantly coincides with solutions andy627/43138440, protalk/43138461. 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.com/blog/entry/8790. Such violation of the rules may be the reason for blocking your account or other penalties.

My submission : http://codeforces.com/contest/1051/submission/43138461 andy's submission : http://codeforces.com/contest/1051/submission/43138440

It was an accident, and I have some evidence for my innocence. Please read my claim carefully. @MikeMirzayanov

  1. Coinciding with my submission??? Of course, it was just a mere coincidence.
  2. This solution has high percentage to write similar code. As the dynamic programming idea is widely used and the abbreviation. "d" or "dp" is commonly used as the variable name, it is very likely that two non-related people could write similar code.
  3. The coding style is mine. If you see other submission of my code, there is my own-made abbreviation.
  4. The difference of submission number is too small. Do you really think that tiny nick of time is enough to share (or copy) and change to my code? Only that I submitted later could be my fault?
  5. I participated with my school club members in dormitory with silence. Since Codeforces is usually held over midnight in Korea and our school is dormitory school, we participate with club members. There was some participants like lgm9, bchan0524 who are same club members with me. They are witness who could prove my innocence.(I would list more students of my club that participated in the round)

As I didn't perform well on the contest, my rating was supposed to fall down if this contest was rated. But I think this misunderstanding should be revised and as I'm purely innocent with this case. Thank you for reading this and please consider carefully with this case.

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

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6 years ago, # |
  Vote: I like it +58 Vote: I do not like it

There are 16 distinct dp transitions, and the order of them is exactly the same is both submissions. The chances of that are infinitesimal. And the differences in your codes are all really small, only aesthetic, like someone was just trying to make it look different. Submission times can be explained by first copying, then submitting at the same time. Sorry, but I don't think I trust you.

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    6 years ago, # ^ |
      Vote: I like it +6 Vote: I do not like it

    Um actually it is not infintiesimal rather 1/(16)!.

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    6 years ago, # ^ |
    ← Rev. 2   Vote: I like it +6 Vote: I do not like it

    Actually the situation doesn’t look like as you see. First, that dp solution was the only solution that comes up to my mind after i saw the problem. This would be same for most of the people. Actually, even i was trying to make dp transitions like that. Also, the order is not that fishy. Normally, people usually make their dp in ascending order. That order is so normal that i bet there are more people out there who coded exactly same order like that. Even i tried to make dp like that in same order if i didn’t find that it could be abbreviated to several lines.

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    6 years ago, # ^ |
      Vote: I like it +6 Vote: I do not like it

    Also, if he was trying to copy his code, don’t you think he would change his code in order to make his code different from andy?

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

I agree that chances of this happening are really small, however there were over 4e7 of sumbissions on CF, so chances of this happening at least once per 4e7 sumbissions are not so small. So I trust you. Also, one code has j<k and other has j<(i<<1). I think it would be strange for making such changes while having all other code almost unchanged.

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6 years ago, # |
  Vote: I like it +22 Vote: I do not like it

Uhh you're both from South Korea and you both go to science high schools. Come on bro..

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    6 years ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    Sorry but what do you want to say? Does that make situation that I can get code for him? There are so many science high schools in South Korea and most of their students participate Codeforces. I doubt that living in same country could be the appropriate reasons for such accusations. Furthermore, I have some evidences and eyewitnesses.

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6 years ago, # |
  Vote: I like it +13 Vote: I do not like it

notorious_coincidence.png

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