harniver's blog

IIOT — Open Contests 2020/21 — ROUND 2 announce
By harniver, history, 4 years ago, In English

The second round of the IIOT (International Informatics Olympiads in Teams) is starting next Tuesday, December 15th 2020! In the meanwhile, you can enjoy our teaser below and try to guess the next eight problems from the hints :)

If you missed the first round, you can still join in; check this post for further details. The mirror contest will be 3 hours USACO-style, starting from 14:30 in the CEST/CET time zone, and ending 24 hours after that.

We hope that you will join us or encourage your students to do so!

Giorgio Audrito (on behalf of the Italian IIOT organizers)

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Comments Comments (19)
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4 years ago, # |
  Vote: I like it +35 Vote: I do not like it

I think Kaey and his team are going to win this round. rocks03's team also has a good chance.

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4 years ago, # |
← Rev. 2   Vote: I like it +18 Vote: I do not like it

Will there be detailed editorials for the problems?

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

    As far as I know, only the official solutions will be released, but I might write an unofficial editorial a few days after the round, possibly with some help from other contestants.

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

      Unofficial editorials would be great, because I think the IIOT problems are really interesting and could learn a lot by upsolving those that I didn't manage to do during the contest.

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

armyalpaca will win

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

try to guess the next eight problems from the hints

1) You have $$$N$$$ planes that move in the 3D space, starting from $$$(x_i, y_i, z_i)$$$ with speed $$$(vx_i, vy_i, vz_i)$$$. If, in some moment, four planes are located in the same plane, an interference will happen. How many times will there be an interference, from the start to $$$k$$$ seconds later?

2) A and B play a game. On each turn, they throw $$$d$$$ different dice. Let $$$k$$$ be the sum of values on the dice; the current player must put $$$k$$$ cards on distinct cells of an $$$n \times m$$$ grid. If a rectangle entirely filled with cards, with area $$$\geq x$$$, appears, the current player wins. What's the probability that player A wins, if both players play optimally?

3) I have to finish homework, please continue claiming problems

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

is multiple devices allowed?

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

Nice spaghetti round!

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4 years ago, # |
← Rev. 5   Vote: I like it +37 Vote: I do not like it

Top teams:

Full standings: ranking.pdf

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4 years ago, # |
  Vote: I like it +5 Vote: I do not like it

Will problems be posted somewhere so we could upsolve them? Also, will any editorial be written for them?

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    4 years ago, # ^ |
    ← Rev. 3   Vote: I like it +14 Vote: I do not like it

    The mirror contest is still running at mirror.squadre.olinfo.it and will end tomorrow. The problems are usually published on the training platform, soon after the mirror ends.

    As far as I know, only the official solutions ( C++ and python implementations, but no explanation) are released. I am currently working on an unofficial editorial, though, which I will post here.

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      4 years ago, # ^ |
        Vote: I like it +5 Vote: I do not like it

      Thanks for the info and I'm waiting to check your editorial!:) Good luck!

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