Kaey's blog

IIOT — Open Contests 2022/23 — ROUND 2 Announcement
By Kaey, history, 23 months ago, In English

The second round of the IIOT (International Informatics Olympiads in Teams) is starting on Tuesday December 13th 2022! The open contest will be 3 hours USACO-style, starting from 17:30 CET, and ending 27 hours after that. In the meanwhile, you can enjoy our teaser below and try to guess the next nine problems from the hints :)

This contest, of a lower difficulty level than the IOI, is intended for teams of 4 contestants from the same high school (check this post for further details). However, everyone is welcome to participate to the open contests!

If you want to participate, you must:

  1. Visit the contest website: https://mirror.squadre.olinfo.it/
  2. Click the link "register", fill out the form and then click on the register button and then "back to login"
  3. You can now log in with the same username and password you used to sign up
  4. If the login is successful you will be ready to participate, just wait for the contest to start! (and maybe save the page in your bookmarks, so that you can quickly get back to it when the contest begins)
  5. When the contest starts, you will see a red button. Click it when you want to start your 3 hour time window!
  6. The ranking for each contest will be available at https://mirror.squadre.olinfo.it/ranking/ after the start of each contest
  7. The tasks will also be available for training in https://training.olinfo.it/#/tasks/ few days after the contests
  8. Good luck and have fun!

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

Tommaso Dossi (on behalf of the Italian IIOT organizers)

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23 months ago, # |
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I can't see any link to register when I visit the contest website

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    23 months ago, # ^ |
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    It will soon be available

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23 months ago, # |
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Will the mirror contest start at 17:30 CET itself or 3 hours after that(after the end of onsite contest)?

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    23 months ago, # ^ |
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    The mirror contents will start at 17.30 CET. Onsite contest begins at 14.30.

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      23 months ago, # ^ |
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      Is the site supposed to throw an error page till 17:30 CET?

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        23 months ago, # ^ |
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        We are activating it right now.

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23 months ago, # |
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How to solve constarr?

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    22 months ago, # ^ |
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    It might be late, but I'm reading the comment now and nobody has answered (yet)

    • (optional) set K -= N*L and R -= L (with the appropriate modules)
    • let cnt[len][sum] denote the number of arrays of length len and sum (mod m) sum
    • you can easily compute cnt[1]
    • knowing cnt[a] and cnt[b] you can compute cnt[a+b] in $$$O(M^2)$$$
    • at this point the solution is very similar to fast exponentation (or any other d&c)
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