This round features Picat, a language somewhat similar to Prolog. We tried to make most of our problems convenient to solve using declarative approach.

The traditional A+B program (A and B are space-separated) looks as follows:

main =>
  A = read_int(),
  B = read_int(),
  C = A + B,
  println(C).

The main source of information about language is http://picat-lang.org/ The contest uses version 0.9.

Hello, Codeforces!

I'd like to invite you to Codeforces Round #297 (Div. 2). It'll be held on Thursday, March 26 at 19:30 MSK and as usual Div. 1 participants can join out of competition.

Great thanks to Maxim Akhmedov (Zlobober) for helping me preparing the contest, to Maria Belova (Delinur) for translating the statements into English, to Mike Mirzayanov (MikeMirzayanov) for the great Polygon platform and ideas of some problems and to my old friends Pavel Kholkin (HolkinPV), Ilya Los (IlyaLos), Vitaliy Kudasov (kuviman) and Arthur Svechnikov (ikar) for writing solutions.

The scoring distribution will be announced later. Good luck everyone!

UPD The scoring is smooth dynamic (with steps of 250 points). More information about this can be found here. Tasks will be arranged in order of ascending supposed difficulty.

UPD2 Competition completed! Thank you all!

UPD3 You can find editorial here.

UPD4 Congratulations to the winners!

1. cikofte
2. fcspartakm_2
3. stealife
4. GITLER228
5. alpq654321

Hello!

VK Cup 2015 — Round 1 (unofficial online mirror, Div. 1 only) — is public unofficial replay of Round 1. It means that if you didn't take part in VK Cup (for example, you are not Russian-speaking), decided to cancel further participation in VK Cup or didn't pass a Qualification you can take part in VK Cup 2015 — Round 1 (unofficial online mirror, Div. 1 only). You should be in Div. 1 to take part in it.

Mostly it will be typical round with regular Codeforces rules. Persons (not teams) will take part in it. The problems will be in English and in Russian. It will be hacks and rating will be updated after it. It will be used recently implemented smoother dynamic problem scores with 250 points steps. You can read about it here.

There were many not Russian-speaking teams in VK Cup Qualifications. I encourage these teams to respect the position of the organizers and not to take part in official Round 1. Please, take part in VK Cup 2015 — Round 1 (unofficial online mirror, Div. 1 only).

Wish you good luck!

Hi everybody! There will be a Codeforces Round for both divisions today at standard time set up by me.

My teammates from ICPC team Moscow SU Trinity sankear and malcolm helped me a lot while preparing this round, also there were lots of useful tips and advices from MikeMirzayanov, applause for them. English translation was made by our veteran translator Delinur.

As usual, there will be five tasks for two hours. The scoring will be announced later.

See you on the round! I hope that each contestant will be able to find something nice in ongoing problems.

UPD: Scoring is standard.

UPD2: Due to technical issues the round is delayed by 15 minutes. We are sorry for an inconvenience.

UPD3: We are sorry for an inconvenience with the task Div1-D. The pretest #16 wasn't satisfying the constraints n, m, k <= 200000. The system testing for the first division will be delayed. If you think that you were affected by this test, you may write me a message and we will make this round unrated for you.

The system testing for the second division will happen shortly, as usual.

UPD4: System testing is complete. Congratulations to the winners!

Div1:

1. piob

2. PavelKunyavskiy

3. dreamoon_love_AA

4. mnbvmar

5. aid

Div2:

1. happyBirthDayBeni

2. ExfJoe

3. _0029

4. tudort

5. kill-z

UPD5: the English editorial was added.