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How I Accidentally Became an OI Problemsetter
By Monogon, history, 3 years ago, In English

The first Codeforces contest I authored included this problem: 1345B - Карточные пирамиды.

Almost 2 years later, the following problem appeared in the Moldovan first state regional of OI:

Now, maybe it's just a notorious coincidence, like when a problem someone authors on Codeforces happened to appear on Topcoder before. In those cases, at least there are noticeable differences in presentation. But the author of this OI problem seems to have magically written the statement in the same way, designed the same picture, came up with the same constraints, and created the same sample test case.

Several questions come to mind. Can contestants have an unfair advantage if some have seen this problem before? Is someone being paid to invent problems for OI and steals an online problem instead? When a problem is used on Codeforces, who owns the intellectual property rights to it? Of all problems I created why didn't they steal a better one?

That's all I have for today, and don't forget to smash that like button.

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Comments Comments (19)
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3 years ago, # |
← Rev. 2   Vote: I like it +104 Vote: I do not like it

smash that like button

<- for people searching where is the like button

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3 years ago, # |
  Vote: I like it +73 Vote: I do not like it

Unfortunately for them, because Codeforces displays only a fraction of a large test file, they weren't able to copy the whole test data from Codeforces...

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

    Hey come on! I was writing about this (you comment wasn't there)

    you can still see my comment below for how they dealt with that ;P

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

      Haha, your explanation seems very plausible considering their laziness, though I really hope they at least thought of generating a test file with 1000 testcases...

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        3 years ago, # ^ |
          Vote: I like it +11 Vote: I do not like it
        Spoiler
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    3 years ago, # ^ |
      Vote: I like it +54 Vote: I do not like it

    As a participant in this Olympiad, I can say that they copied the problem from codeforces and still 2 of their tests were wrong.

    They ended up removing those tests, so this problem was worth only 8 points instead of 10.

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

      If the other problem(s) from this Olympiad was a weird and hard problem stolen from some Russian contest from 20 years ago, then the sector-level Olympiad in Moldova sure looks a lot like the town-level Olympiad stuff I've seen in Romania...

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3 years ago, # |
  Vote: I like it +15 Vote: I do not like it

Monogon:

maybe it's just a notorious coincidence

Also Monogon:

Of all problems I created why didn't they steal a better one?

But LOL how did they steal the test cases? (Codeforces doesn't show the full test case for large test cases). I'll tell you how:

they copied some random accepted solution and the first 10-ish lines visible from the first 10-ish tests and got the correct output from that random AC solution. (or maybe even way less than 10, depending various factors such as laziness, time left until the contest starts... etc.)

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    3 years ago, # ^ |
    ← Rev. 2   Vote: I like it +42 Vote: I do not like it

    Well I'm not saying they stole any test cases (besides the sample). They easily could've generated random numbers by themselves.

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3 years ago, # |
  Vote: I like it +4 Vote: I do not like it

Of all problems I created why didn't they steal a better one?

"Faza de sector" is basically an insult. All the others were too nice ♥

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3 years ago, # |
  Vote: I like it +23 Vote: I do not like it

I want justice for Monogon

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3 years ago, # |
  Vote: I like it +56 Vote: I do not like it

Moldova is officially the best country because they use actually quality problems.

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    3 years ago, # ^ |
      Vote: I like it +53 Vote: I do not like it

    Sad that they can't come up with correct intended solutions for them though...

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3 years ago, # |
  Vote: I like it +10 Vote: I do not like it

As a participant in the Olympiad, I can confirm they reused other problems too, not only from Codeforces.

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

Is someone being paid to invent problems for OI

I highly suspect someone's being paid peanuts to invent problems for OI, and doesn't waste effort.

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3 years ago, # |
  Vote: I like it +71 Vote: I do not like it

ksun48 is also a problemsetter in IOI 2019.

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3 years ago, # |
  Vote: I like it -20 Vote: I do not like it

is it rated?

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    3 years ago, # ^ |
    ← Rev. 3   Vote: I like it +40 Vote: I do not like it

    No. Due to the unethical and ugly behavior of some members of the community, this round will be unrated. Let's solve problems just for fun!

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