Hello Codeforces!

On February 16, 18:05 MSK Educational Codeforces Round 38 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

This round will be rated for Div. 2. It will be held on extented ACM ICPC rules. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.

You will be given 7 problems and 2 hours to solve them.

The problems were prepared by Ivan BledDest Androsov, Sahand Xahandd Alitanloo and me.

Thanks Mike MikeMirzayanov Mirzayanov for great system Polygon!

Good luck to all participants!

UPD: Since there will be another Div. 2 contest soon, the hacking phase will be shorter (only 12 hours). Before CF Round 464 we will actualize the registrations in such a way that Div. 2 will be officially registered, and Div. 1 participants — unofficially.

UPD2: We also have a message from our partners Harbour.Space:

We are excited to announce that some of the world’s strongest teams will come to our Hello India x Russia Programming Bootcamp: MIPT and all top India’s Universities that qualified to the World Finals!

As always, the boot camp isn’t only about the training — we’re in the process of getting renowned keynote speakers from all over the globe to come and speak about life and all the opportunities at your fingertips after ACM-ICPC.

We look forward to seeing you all there this spring! For those of you who haven't registered, there's still time.

Register here

If you have any questions we can help you with, please connect with us:

Phone number: +34 674 291 422 Email Address: [email protected]

UPD3: Editorial is published

The 8th BSUIR Open Programming Championship will be held from February 16 till April 13, 2018 (Minsk, Belarus).

Hello, Codeforces!

I would like to invite you all to the International Coding Marathon 2018, under the banner of Technex'18, IIT (BHU) Varanasi. It will take place on Thursday 15th February 2018, 20:05 IST. The contest will be held as a combined Div.1+Div.2 round which will be rated for participants from both divisions.

The problemset has been prepared by me (TooDumbToWin), DeshiBasara, hitman623, dhirajfx3, karansiwach360 and Enigma27. We would like to express our heartiest thanks to vintage_Vlad_Makeev and KAN for their constant help in preparing the contest and MikeMirzayanov for the amazing Codeforces and Polygon platforms. We also thank AlexFetisov and winger for their invaluable help in testing the problems.

Prizes

• Overall 1st place: INR 35,000
• Overall 2nd place: INR 25,000
• Overall 3rd place: INR 15,000
• 1st place in India: INR 10,000
• 2nd place in India: INR 8,000
• 3rd place in India: INR 6,000
• 1st place among IIT (BHU) Varanasi freshmen: INR 1,000

Participants will have 2 hours to solve 7 problems. The scoring distribution will be announced soon.

Good luck everyone! Hope to see you on the leaderboard.

Update: Scoring is 500 — 1000 — 1500 — 2000 — 2500 — 2500 — 3000

Update 2: Thanks to all participants and congratulations to all the winners. The winners, who are eligible for prizes, will soon be contacted regarding the same.

Overall top 10

1. Radewoosh
2. fateice
3. Um_nik
4. laofudasuan
5. dotorya
6. 300iq
7. LHiC
8. ksun48
9. wxh010910
10. chemthan

Indian top 5

1. PrashantM
2. rajat1603
3. Baba
4. jtnydv25
5. adkroxx

Some problem statements were not clear. We deeply regret the inconvenience caused.

The editorial has been posted here. This was first contest set by most of us, so please help us do better next time by filling this form.

Hello, Codeforces!

I would like to invite you to take part in the 10th jubilee edition of the international programming marathon Deadline24. During the contest, the teams of three tackle algorithmic problems.

Registration will last until February 22 and it is possible through the form available on the website: www.deadline24.pl/register

The qualifying round will take place on Sunday, February 25. During it the registered teams will struggle to solve tasks for 5 hours and this will be verified by server. This part of the competition is carried out remotely. In the last year a record number of competitors registered for the first phase — 1950.

For the final — which lasts for 24 hours — 30 teams with the best scores obtained during the elimination will be invited. The final will take place on 7- 8 of April in Poland. This year the best teams will win: Oculus Rift, iPad and Kindle Oasis 2.

Don't forget that the registration ends on February 22! Good luck in the qualifying round :)

If you are interested in the previous years' tasks, you can find them here.

Special thanks to Mike Mirzayanov for his help in promoting the competition on CF.

Hi, Codeforces! Happy Valentine's Day. And happy Lunar New Year!

I'm quite honored to invite you to Codeforces Round #462 which will take place at 15:05 MSK on 14 Feb and last for two hours.

The authors are quailty, skywalkert, visitWorld and me. This is our second round here.

The round couldn't have been realized without efforts of KAN and our testers: cyand1317, demon1999. Thanks for your help to the contest. Also, thank MikeMirzayanov for the fantastic Codeforces and Polygon platforms.

The contest will consist of five problems and it is rated for both division contestants.

The background of problems will be about Lunar New Year. (Yes... Not Valentine's Day...)

Hope to see you in the contest! Good luck and have fun, wish you a high rating!

We suggest that those who already have Valentine's Day plans should not participate... You can always upsolve a contest, but there is only one Valentine's Day ;)

The scoring distribution will be announced later.

See you in the contest!

UPD: The scoring distribution is:

div1: 500 — 750 — 1500 — 2250 — 2500

div2: 500 — 1000 — 1500 — 2000 — 2500

UPD2: Congratulations to the winners!

Division 1 :

1. Um_nik (solved all problems!)
2. Golovanov399
3. geniucos
4. fateice
5. kriii

Division 2 :

1. aabdelzaher
2. WNG
3. ZYF1023
4. Kita_The_Dragon
5. Kuroni

UPD3: The editorial is available now!

Thank you everyone!

Happy Valentine's Day and happy Lunar New Year!

See you next time!

C++17 is now available on codeforces, community wants new edition of C++ tricks by HosseinYousefi, so, let's start!
Disclaimer: I have done only few examples of new features, which in my opinion are related to competitive programming. Feel free to comment and provide more real-world examples or ask to elaborate some features with more examples or explanations.

Fold expressions

• I think that everybody knows, what reduce or fold means, but a c++11 example:

vector<int> v = {1, 3, 5, 7};
int res = accumulate(v.begin(), v.end(), 0, [](int a, int b) { return a + b; });
cout << res; // 16

• In C++17 there is also folding support for a template parameters list. It has the following syntax:

(pack op ...)
(... op pack)
(pack op ... op init)
(init op ... op pack)

• For example, implement a template function that takes a variable number of parameters and calculates their sum.

Hello everybody!

Yandex.Algorithm 2018 team is glad to announce that the registration for the seventh competitive programming (and even more) championship held by Yandex is open! The championship is a wonderful opportunity to practice with interesting problems, compete against addicted programmers all over the world, and battle for a brand T-shirt. As usual, 25 most successful addicted competitive programmers will be invited to onsite finals that will be held in Saint Petersburg on May, 19.

In case you feel tired of classical competitive programming problems style, or just seek for competitions of any possible kind, you might be interested in new tracks we announce: optimization and ML.

Warm-up round will take place this Sunday!

UPD: link to warm-up round.

UPD2: editorial is here!

Hello!

As an allowed language on Codeforces and Polygon C++17 has been added. The compiler we use is 32-bit mingw64 version 7.2.0 (later will be updated when new versions are released). We are using a patch from halyavin to speed up I/O when using scanf/printf (for more details, read here). The exact used distribution can be installed on Windows from our package manager called PBOX using the link http://pbox.me/packages/mingw-w64-7

The exact compilation command line is:

g++.exe -static -DONLINE_JUDGE -Wl,--stack=268435456 -O2 -std=c++17 -o %name%.exe %1 2>compilation.log

Wish you successful solutions in C++17,
MikeMirzayanov

Hello, Codeforces! Haven't seen ya for a while :D

Codeforces Round #461 will take place on Wednesday, 20:15 MSK. Note that the round is scheduled a bit later than usual.

The round will be rated for all division 2 participants. Division 1 is heartly welcome aswell :)

My gratitude to Kolya (KAN) for round coordination, Grisha (vintage_Vlad_Makeev), Oleg (xen), AmirReza (Arpa) and Senya (craborac) for testing and Mike (MikeMirzayanov) for awesome Codeforces and Polygon. A special thanks goes to Dima (Dmitriy.Belichenko) and Camille (pseuda) for sharing a problem sketch with me.

The main character of this round will be Imp the playful monster. Yet the statements are guaranteed to be short :)

There will be six problems with the following scoring:
500 — 1000 — 1250 — 1500 — 2000 — 2750

GL & HF!

Note that the round has been moved 40 minutes later to avoid clashing with CSAcademy Round.

UPD. The contest is over. Well...

UPD. System testing is over! Editorial.

Congratz to the winners!

Div. 2:

1. sorry-haghani
2. I_hate_Shadow_Light
3. SashaShlyapik
4. Pojiloy_gibon
5. Marisa

Div. 1 (unofficial):

1. dotorya
2. Vercingetorix
3. dreamoon_love_AA
4. kmjp
5. Anadi

UPD. The complete editorial is out (D/F).