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)
I think Kaey and his team are going to win this round. rocks03's team also has a good chance.
taulant will win this round because of purple supremacy.
Datteo Mamiamo will destroy anybody else imho.
davi_bart is going to win, but if to_mare will score some points we have a chance.
true
We all know TheScrasse team is going to win, especially with math problems
The truth
I was desperately trying to debug stringstreak (it failed on exactly 1 testcase). There was 1 minute left. Suddenly, I heard a shout from matte2772. He did 90 points on dungeon (apparently, the hardest problem in the contest), and here is his code.
Will there be detailed editorials for the problems?
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.
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.
armyalpaca will win
try to guess the next eight problems from the hints1) 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
is multiple devices allowed?
Yes.
Nice spaghetti round!
Top teams:
# | pts | team name | members with a Codeforces handle
1 | 774 | Btwice | Kaey, Darkeld, avirarf
Full standings: ranking.pdf
Will problems be posted somewhere so we could upsolve them? Also, will any editorial be written for them?
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.
Thanks for the info and I'm waiting to check your editorial!:) Good luck!