The final round of the Finnish Olympiad in Informatics (Datatähti) will take place tomorrow, and after the official contest, there will be an international online contest.
The online contest will be available at CSES:
The length of the contest will be 5 hours, and there will be 6-8 tasks of varying difficulty. The contest will follow the IOI rules: full feedback and no penalty for multiple submissions. Available languages are C++, Java, Pascal and Python.
The online contest will be a virtual contest, which means that you can start the contest at any time between 18 Jan 2018, 20:00 and 21 Jan 2018, 15:00 (UTC).
Is there an estimation of how difficult the problems will be?
Last year's contest is here: https://cses.fi/95/list/
The difficulty will be about the same.
The contest has now started!
Is there going to be an international scoreboard like in last year's contest?
Results: https://cses.fi/162/scores/
Congratulations to ainta for winning the contest with 629 points!
The best score in the official contest was 517 (by Kuha and siiri).
Lol rank 2 again like last year.
What's the intended solution for P7?
Will there be an editorial?
At the moment no, but you can see all the submissions in the scoreboard and ask further questions here if necessary.
Solution to E? I tried writing a binary search for the lower bound but it got way too complicated. These ACers are working some coding magic
It can be done with a binary search. We try to binary search the highest upper bound of passengers x such that there are no solutions. If there is a solution, then you want to keep the number of passengers as close to the upper bound x as possible without exceeding it. You'll also need to ensure that after leaving a station the number of remaining passengers r is greater than or equal to the number of passengers currently in train, so you'll need to update the upper bound x to min(x, r).
How to solve F?
Shameless self-promo
It can be proved the two problems have the same result for a >= 2. a = 1 is just... trivial.
So this problem is just the problem in the link with an additional constrain on a?
And a player can create new heaps of coins, but this does not change the winning condition in the no-constraint game. However, without this condition, the constrained version may be very different.