Kaey's blog

IIOT — Open Contests 2024/25 — ROUND 1 Announcement
By Kaey, 6 weeks ago, In English

The first round of the IIOT (International Informatics Olympiads in Teams) is starting on Monday November 11th 2024! The open contest will be 3 hours USACO-style, starting from 17:00 CET, and ending 27 hours after that. In the meanwhile, you can enjoy our teaser below and try to guess the next 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/ for the standard division or https://mirror-esordienti.squadre.olinfo.it/ for the debutant division.
  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/ or https://mirror-esordienti.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)

  • Vote: I like it
  • +29
  • Vote: I do not like it

»
6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I can see the following on the standard division link ( https://mirror.squadre.olinfo.it/ )

The contest has already ended.

The contest started at Nov 4, 2024, 12:00:00 AM and ended at Nov 9, 2024, 11:59:59 PM.

Is the contest really over?

→ Reply
  • »
    »
    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    We held the practice contest on the same site. The practice round is over, but everything will sblw correctly once we set the contest up.

    → Reply
»
6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

What's the difference between standard division and debutant division

→ Reply
»
6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

is it necessary to have participants from same school and is it allowed to participate individually?

→ Reply
  • »
    »
    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    from this blog:

    spoiler
    → Reply
»
6 weeks ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

Can we register a team for the online mirror?

→ Reply
»
6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Thanks to all the organizers, it was a great contest!

Would you mind explaining how to solve azugand and binarygrid?

→ Reply
  • »
    »
    6 weeks ago, # ^ |
      Vote: I like it +9 Vote: I do not like it

    The editorial will be available soon, but here are some hints:

    Hint for azugand
    Hint for binarygrid
    → Reply
    • »
      »
      »
      6 weeks ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Oh okay, I thought the editorial won't be published as it's not a regular CF round. Anyways, thanks for the hints.

      → Reply
»
6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

How to solve task "Expansion land"?

→ Reply
  • »
    »
    6 weeks ago, # ^ |
      Vote: I like it -21 Vote: I do not like it

    fft

    → Reply
    • »
      »
      »
      6 weeks ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      I am asking for the formula not for the algorithm you used to calculate it:).

      → Reply
      • »
        »
        »
        »
        6 weeks ago, # ^ |
        ← Rev. 3   Vote: I like it 0 Vote: I do not like it

        $$$2^k =$$$ number of subsets of connected components. A subset of connected components

        • must be a union of original connected components;
        • must not have edges going outwards.

        If a subset has $$$x$$$ nodes, you cannot draw $$$x(n-x)$$$ edges (but you can decide to draw the other absent edges or not). So you have to calculate the number of subsets of original connected components with $$$x$$$ nodes in total for each $$$x$$$, and this can be done with knapsack and made faster with FFT.

        → Reply
»
6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I solved Azugand in contest!

→ Reply