### 300iq's blog

By 300iq, 3 years ago,

If you are a school student and love programming competitions, enjoy solving mathematical and logical problems, designing, and implementing algorithms and data structures – we invite you to participate in the International Olympiad in Informatics — Innopolis Open.

The contest is one of several international Olympiads annually held by Innopolis University. The best high school students from different countries compete in the prestigious competition to sharpen their informatics skills.

3 steps to win!

• Sign up until November 22, 2020 choosing a category: Informatics. For Russian speaking countries, the registration is here
• Pass the Qualification Online Round. There will be 2 independent online contests, you can participate in both contests. The best result of two contests will be taken to get to the Final Stage.
• 1st Qualification Online Round: November 22, 2020 at 10:00 a.m. (UTC +3), duration — 5 hours
• 2nd Qualification Online Round: December 13, 2020 at 3:00 p.m. (UTC +3), duration — 5 hours
• Be on the Final Stage at Innopolis University (we hope it would be on-site, not online) on February 20-21, 2021.

• +80

 » 3 years ago, # | ← Rev. 2 →   +21 I recommend you to participate!
•  » » 3 years ago, # ^ |   +5 I recommend you to participate too!
 » 3 years ago, # |   +8 Hey 300iq. The Sign Up link seems to be broken (both for Russian and other speaking countries). Could you fix it? It redirects to a Codeforces page in russian saying URL not found on server.
•  » » 3 years ago, # ^ |   +6 Fixed, sorry!
 » 3 years ago, # |   +13 Serbia and Montenegro are two separate countries. Can you please fix that?
 » 3 years ago, # |   +11 Is it okay, if we discuss the problem of day-1 now? If yes, then can anyone please explain the solution of E for 100?
•  » » 3 years ago, # ^ |   +41 Answer is at most 4, it's not that hard to check whether the answer is $\leq 1$, $\leq 2$ or $\leq 3$. The harder part is to check whether the answer is zero i.e. there's a nice shape of rooks originally. It can be solved in $O(n \sqrt{n} \log{n})$. Basically iterate over rows if the row contains $\leq \sqrt{n}$ rooks perform a bruteforce and note down every pair of columns in that row in a map, if we find a pair that has already occured in another row we found a rectangle. If we have a row with $>\sqrt{n}$ rooks loop through all the rows and try to find a row with two common columns.
•  » » » 3 years ago, # ^ |   0 Thanks a lot! Your solution gave me a new way of thinking :D
 » 3 years ago, # |   0 Weak test data in problem E.I was coding nroot(n)*log(n) solution for E and made a stupid bug but my code got AC and I realized that it should get tle.so I wrote quadratic solution(for checking if answer 0) and that also got AC without breaking if answer=0. Test Case- n=50000 1,1 1,2 2,1 2,2 .. .. .. 25000,1 25000,2 code — https://ideone.com/JmcEtB I have tested this in custom invocation.it gets tle even in 15s.
 » 3 years ago, # |   +17 I just got a mail from the email I used to participate in the qualification round 1. Should I have to sign up again? I am a bit confused.
 » 3 years ago, # |   0 I signed up to contest in Informatics but there isn't any login id password or any contest link in mine mail or in mine phone. What can i do?
 » 3 years ago, # |   +16 Will any type of editorial would be given for the qualification rounds? If yes, where we may get it?