Hi all!

Authors of today's round are craus and dalex. We just couldn't miss the round with such a beautiful number, so at 19.30 MSK you will solve problems which were invented by Pavel and prepared by me.

We thank Gerald and Delinur for their help in contest preparation and MikeMirzayanov for creating Codeforces.

Scoring system and score distribution will be published when the round starts. Anyway this information makes no sense unless the round begins.

We wish you accepted solutions and successful hacks!

UPD. Contest is over, congratulations to the winners!

Div. 1:
1. Petr
2. tourist
3. Egor

Div. 2:
1. k3e18
2. tongcx1988
3. LeMieux

UPD. 2 Problem analysis is published.

Hello, Codeforces.

UPD: Mashup feature is disabled until the end of the round. This is temporary and won't happen in the future.

Today we want to present you with our latest feature: mashup contests.

Hi, Codeforces Round #221 will take place on December 24th at 18:00 MSK for both divisions.

Problem setters are whd, oGhost and boleyn.su. This is our first Codeforces Round, and we hope it will be a good one.

We'd like to thank Gerald and alpc104 for helping us prepare this round, and MikeMirzayanov for bringing all of us a place to compete and communicate with others.

The score distribution will be announced before the contest starts.

UPD1: The score distribution is 500-1000-1500-2000-2500 for both divisions.

UPD2:

Congratulations to winnners and Merry Christmas to ones who celebrate it today!

Div 1:

1.Touma_Kazusa

2.al13n

3.rng_58

4.hmspmy077

5.uwi

Div 2:

1.bohuss

2.Tyg3R

3.xhsong

4.adamant

5.Kira96

I've found some time to support JavaScript, which is so popular now. I chose V8 as the most developed implementation of JavaScript.

With the help of a tambourine and a liter of cola I successfully compiled it on Windows. Funny, I was ready to implement workaround to support reading from stdin in JavaScript, but d8 already supports it! Just use readline() to read line from the input.

Here is an example of A+B:

var line = readline().split(' ')
print(parseInt(line[0]) + parseInt(line[1]))

Interesting fact, that if there is no line-break (\r\n) at the end of line, then readline() returns undefined. So it is one more reason for good rule: each line should end with eoln.

As a tiny research I've implemented HeapSort on C++, Java and JavaScript. I have an opinion that all dynamic typed languages are very slow. But...

I've implemented HeapSort on 10⁷ elements from 0 to 9999999. I think it is good benchmark to show how fast can be your code if you write like in Pascal or pure C. The result have surprised me:

JavaScript shows very good performance! I understand that such kind of code is very good for optimization and jit-compilation, but I'm impressed. By the way, Java with its optimized JIT is not as good as it can be.

Actually, I posted the codes in github. You may implement the same algorithm on your favorite language. Here are links to current implementations:

• С++
• Java
• JavaScript
• Pascal
• Python 2
• Python 3
• Ruby
• Scala
• Go
• D
• C#

You may post links to pastebin in comments or give submission id. Better to do a pull request.

If you are planning to write implementation, please write it neat and tidy. Write it as closer to the C++, Java and JavaScript as possible.

UPD 1. With the help of alexei-zayakin, Pascal has been added.

UPD 2. With the help of gchebanov Wizmann and juancate I've added Python 2, Python 3, Ruby, Scala, Go.

UPD 3. Here is V8 (Windows binaries).

UPD 4. I've updated some compilers and the benchmark results.

UPD 5. Added D. Thanks Gassa.

UPD 6. Added C#. Thanks gmogelashvili.

Hi! Soon Codeforces Round #220 (Div. 2) will take place, i am the author, Dmytro Berezin. This is my third round and Sereja still hopes, that this is the last :)

Everything changed since last round. Dima and Inna have thought about their behavior and asked Sereja to excuse them. They are good friends now. You should make the family happiness even stronger!

Thanks to Gerald Agapov (Gerald) for the help in round preparation, Maria Belova (Delinur) for tasks translations, Mike Mirzayanov (MikeMirzayanov) for perfect system, and Sergii Nagin (Sereja) for his agreement (not to post here another photo) to help in testing.

Points distribution will be. 500-1000-1500-2000-2500. Here we go :)

Hello, Codeforces.

Today group functionality was updated and extended:

Here is a list of changes:

• Personal blog entries now can be attached to the group blog.

• New blog entries can be written directly to the group blog. Such entries won’t be displayed in recent actions and votes for it or for it’s comments will not affect contribution.

• Only managers can write or attach entries to the group blog. Entries can be read by and commented by all group members.

• New group role was added. Now there are three group member types: spectator, participant and manager. Spectator is a group member, which can not register to the group contest and is not displayed in group standings. But spectator can see the standings, see the problems, read and comment group blog. For example, if you want someone to see the trainings of the group, but not to participate, you can invite the user as spectator.

• Spectator registration policy can have same values as participant registration policy. Spectator registration policy can not be more strict that participant’s one. By default it is set to be the same as the participant registration policy.

• Also, there is an additional registration policy for spectators – automatic registration. It means that anonymous and non-member users will be considered spectators. They will not be displayed in group members table. For example, if you want to organize the championship of your university, you can create a group, invite only official participants of the contest as group participants and set spectator registration policy to automatic. So only official participants will be able to register to the contest and take part in it, but standings and problems will be open to public.

• There were changes in the security policy of the group web pages. To access a group web page, user must be a group member. To all anonymous or non-member users to see the web pages of your group, you must set spectator registration policy to automatic.

With best regards, Ivan.

Hello.

Codeforces Round #219 will take place on December 13th at 18:00 MSK for both Div.1 and Div.2 participant. Make sure that it will be held unusual　time.

Problem setters are kagamiz and DEGwer, and we thank Gerald for helping us to hold this contest, and Delinur for the translation, and MikeMirzayanov for systems.

The score distribution will be uploaded soon, but probably we use the standard scoring system.

UPD1: The score distribution is standard, 500-1000-1500-2000-2500 for both division.

UPD2: Problem B from Div.2 and problem C from Div.1 have some problems, so all submissions to these problems are rejudged. I'm very sorry.

UPD3: Anyone who gets AC two or more times, because of resubmit before clarification, please, write to Gerald, your submissions that should be skipped. Sorry for inconvenience.

UPD4: Now system test has finished, congratulation for winners!!!

Division 1:

1.jqdai0815

2.tourist

3.PavelKunyavskiy

4.dasko1

5.al13n

Division 2:

1.Hwhitetooth

2.pcnc_zLq

3.wuyiqi

4.prok

5.aaaaajack

And also congrats for rng_58 and permin, who got AC on Div.1 E problem!!

UPD5: Now editorial is uploaded here.

Greetings to the Codeforces community!

Today in Saratov there is a second day of the local school competition, so we again introduce you a round based on school problemset. Round is for participants from Division II. Members of the first division can participate out of competition, as usual.

Round starts on 8-th of December at 09:00 UTC

Problems were prepared by employees and students of Saratov State U, including MikeMirzayanov, Fefer_Ivan, NALP, HolkinPV and me.

Scoring: 500-1000-1500-2000-2500.

UPD: Congratulations to the winners:

1. asalwaysdontbeahero
2. VKRNVO5
3. chnluyi
4. pkwv
5. Xe4NIK

UPD: tutorial.

Please take a notice that recently the schedule has been changed. Twice.

Greetings to the Codeforces community!

I'm glad to announce that we again decided to introduce a round based on one of the programming olympiads for schoolchildren in Saratov. This time it is a round for participants from Division II. Round will start at unusual time for Codeforces: Dec. 7, 07:00 UTC.

The problems were prepared by employees and students of Programming Competitions Training Center of Saratov State U.

Members of the first division can participate out of competition, as usual.

Currently we are planning to use dynamic scoring system.

UPD: Moved from 09:00 to 07:00 because of Kotlin Challenge.

UPD 2: Tutorial has been published.