Edit: The problemset will be used in OpenCup round and so, if you are taking part, please do not discuss the problems(or view the standings) until Nov 22, 2015.
CERC 2015 is over. University of Warsaw, University of Wroclaw and Jagiellonian university qualified. Comenius University, University of Zagreb and Charles University of Prague are also likely to qualify. Congratulations to all these teams.
I am neither European nor do I have any affiliation towards the contest but I needed to congratulate Swistakk, Marcin_smu and mnbvmar for their clean sweep :D
Good luck at the ICPC finals!
Could please add the contest to the gym? :)
OK, so since thread about CERC was created but with not much info, I will try to add some more context:
Teams which are going to finals:
1. University of Warsaw — Wojtek Nadara (Swistakk), Marcin Smulewicz (Marcin_smu), Marek Sokołowski mnbvmar
2. University of Wrocław — Bartłomiej Dudek (bardek), Maciej Dulęba (Solaris), Mateusz Gołębiewski (matix2267)
3. Jagiellonian University — Szymon Łukasz (noh4h_ss), Krzysztof Maziarz (krismaz), Michał Zając (zaj) (don't be misled by their ratings :P)
Teams which are very likely going to finals (probably going to be confirmed soon):
4. Commenius University — Michal Anderle, Eduard Batmendijn (Baklazan), Jan Hozza (jablko)
6. University of Zagreb — Ivan Lazarić (IvL), Mihael Liskij (Mihaell), Tonko Sabolčec
10. Charles University in Prague — Matěj Konečný (Shulik), Václav Rozhoň (zaspagety), Štěpán Šimsa (simsa.st)
Problems were really nice in general and we enjoyed solving them. There were also no technical issues, contest was really smooth from organizational side.
Here was a part where I discussed one problem, however I removed it on snarknews' request (hidden till 22 Nov)
However as I said earlier, we really enjoyed contest, issues which I've described are not that critical to destroy overall good impression :P.
Statements will be available after that problemset will be used in OpenCup.
Organizers here. Thanks for your comments. We were aware of first issue in problem F and let me explain our thought process. Making modulo smaller doesn't really work because we would have to make it smaller than N which would make problem solvable in easier ways. The precision issues with FFT can be easily fixed (we thought most of the teams who solve the problem will do that). All you have to do is to write one polynomial as weighted sum of two smaller ones, for example a_i = x_i * 1000 + y_i. Now instead of convoluting with a_i we convolute with x_i and y_i separately and add the results appropriately. Price we pay is more convolutions but precision is no longer an issue. If module were higher we can do the same with both polynomials, or even write them as sum of more polynomials each. Also, we raised the time limit in case teams decide for Karatsuba's algorithm which has no precission issues. Regarding the second issue, yes, we screwed up and we are sorry. We are not the best matematicians and we will surely find IMO gold medalist to test out next CERC problemset :). P.S. Problem statements and contest data will be available on Nov 23.
Nonetheless, thanks for awesome contest, it was nearly flawless!
I can't understand why we have to wait the whole year for next CERC in Zagreb :]
Hidden till Nov 22.
Please do not discuss problems till Nov 22, because the OpenCup stage is planned on it. Thanks.