UPDATE: the editorial is here

Hello CodeForces! This year again, I'd like to invite you to the online mirror of an open championship of Switzerland called HC2 (the Helvetic Coding Contest). A mirror was also held last year and two years ago.

The Helvetic Coding Contest is a yearly contest held at the EPFL in Lausanne by the PolyProg association. The contest itself took place on March the 17th, but the online mirror is scheduled on Saturday, 14th of April, 10:05 Moscow time. The duration is 4:30.

Rules:

• you can participate in teams or individually (1-3 people),

• standard ACM-ICPC rules (no hacking),

• the contest is not rated,

• if you have participated in the onsite contest, please do not participate in the mirror.

The contest this year is Star Wars-themed. It features 6 series of 2-3 related tasks with increasing difficulty (easy/medium/hard). Sometimes it may be the case that a solution for the hard version solves all of them, but usually not. We think that the problemset is diverse and interesting, and while the contest is ACM-style, you will find that some problems are not so standard. Most easy&medium problems are even solvable in Python, so you can also recommend this contest to your newbie friends :) We promise to post a nice editorial as soon as the contest ends.

Acknowledgments: the problems were set by maksay, boba5551, mukel, DamianS, esrever, and myself. Thanks also go out to people who helped with the statements and testing: bgamlath, Michalina Pacholska (who also draws the cows), and KAN for CodeForces coordination, as well as everyone involved in the actual onsite contest, who are too many to name here. We also thank the sponsors Open Systems and AdNovum. Lastly, thanks to MikeMirzayanov for CodeForces and Polygon (which was used to prepare the problems).

Finally, in a bit of autopromotion, note that you can use Hightail to automatically test your solutions :) Good luck!

After-contest UPDATE:

>>> Editorial <<<

Feel free to ask questions in this topic.

Thanks to everyone who participated! We hope you have enjoyed the problems despite the interruption in judging. The top 4 teams, who have solved all problems, are:

1. SpicyFriedTomatoes: AbstractKangaroo, jqdai0815

2. (｀・ω・´): King_George, ohweonfire, FizzyDavid

3. ymd队长ioi捧杯超稳: sunset, TLE, yanQval

4. ★SweeT DiscoverY★: dotorya, molamola., zigui

See you again next year!

Hello Codeforces!

On April 10, 14:35 UTC Educational Codeforces Round 42 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 one day 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 me and Alex fcspartakm Frolov.

We'd like to thank Nikolay KAN Kalinin, Grigory vintage_Vlad_Makeev Reznikov, Vladimir vovuh Petrov for the testing and help in preparing the round.

Good luck to all participants!

UPD: Some information from Harbour.Space U

The third Hello Programming Bootcamp finished as teams from around the world learned, competed, and got to know each other in the cities of Kollam and Moscow.

“I'm positively surprised with the level and number of Indian teams. I believe when following a systematic and regular training schedule — they will certainly attend top world records in programming” says Mike MikeMirzayanov Mirzayanov.

The results of the India boot camp are as follows:

We would like to congratulate the top teams from the India side in both divisions A and B — and especially recognise division A’s winner: Team SDV — Vasily platypus179 Alferov, Vaibhav gvaibhav21 Gosain, Motasem Motarack AL-Kayed sponsored by Social Discovery Ventures, and winners of the Educational Codeforces Round 39.

The division A winners are: Team SDV (platypus179, gvaibhav21, Motarack), TheVindicators (IIIT Kharagpur) (pranjal.ssh, Chenghiz), DomiNUS (NU of Singapore) (vodanhna, darknsux, minh141198).

The division B winners are: BEU Programmers (Baku Engineering University) (mahmud2690, Mamedov, fuck_coderinuse), Penza State University (Fortin, WooDeND, Key_J) and Sab_lite_hai (IIT(BHU),Varanasi) (Enigma27, Dsingh_24, nitishk24).

All results from India side
All results from Russia side

From the ever present in ACM World Finals city of Moscow, to the new-comer on the world stage city of Kollam — Hello India x Russia Programming Bootcamp showcased heart, passion, and a universal drive towards a better competition.

“It's the first time I participate at Hello ACM-ICPC Bootcamp in Asia and I admire local hospitality and students motivation. Everyone seems to be eager to learn, participants stay very late upsolving the contest problems and revising the topics they were thought during the day” states Gleb GlebsHP Evstropov, The Coordinator of the Programming Committee.

The latest in world finals simulation training would not be possible without the bronze sponsorship of VTB, the institute with the most extensive international network of any Russian bank, boasting more than 30 banks and financial companies in more than 20 countries.

Fill out this form and we will keep you up to date on our next boot camp!

UPD: Tutorial

Hi everybody! Tomorrow at 12:00 UTC there will be the third round of Yandex.Algorithm 2018. You can enter contest from the Algorithm main page.

This round is written by me with a great help of GlebsHP and everybody who was testing the round. While solving the problems, you will be helping some of my colleagues here at Yandex to deal with some practical (or not) situations. Good luck to everybody!

UPD: Round is over! Congratulations to Merkurev, jcvb and Um_nik who got first three places in the standings.

The elimination stage is over and we can now find out who are the contestants that are going to compete in the Algorithm Finals in Saint Petersburg: elimination scoreboard.

There is also a round editorial (ENG only) available.

Good luck and see you later!

Hi Codeforces!

Programming Club, IIT Indore and Euristica 2018 are proud to present our flagship event, Divide By Zero! The contest will take place on Saturday, 7th April at 9:35PM IST.

Prizes : Codeforces T-shirts for top 15 participants overall and top 15 participants in India.

Thanks to the following people for making the round possible :

• apoorv_kulsh, arnabsamanta, AakashHanda, Vicennial, kr_abhinav, 7dan, rohitranjan017 and myself for setting the problems.

• usaxena95 and killer_bee for their help with the problems.

• 300iq and demon1999 for testing the problems.

• vintage_Vlad_Makeev for coordinating throughout the round.

• fcspartakm and arsor for translating the problems.

• KAN for his invaluable help with the round.

• MikeMirzayanov for the amazing Codeforces and Polygon platforms.

There are 8 problems, and 2.5 hours to solve them. The points distribution will be updated later.

Euristica, sponsored by Arcesium is the inaugral Programming festival of IIT Indore. It comprised of 10 events this year, spanning across various domains like Competitive Programming, Application Development, Cyber Security and Machine Learning. For more information, visit www.euristica.in .

Hope you guys enjoy the contest! See you on the leaderboard!

UPD: The scoring distribution is 500-1000-1500-2000-2250-2500-3000-3500.

UPD 2: Do give your feedback here : https://goo.gl/forms/xbsdMxnkA3XsG4092. Would love to hear your feedback, since that would help us get better!

We hope you guys enjoyed the contest and found the problems interesting.

UPD 3: You can find the editorial here.

Here are the list of winners who won Tshirts. We will contact you guys soon. Congrats!

Overall Top 15:

1. jqdai0815

2. Benq

3. Syloviaely

4. ainta

5. ko_osaga

6. dotorya

7. Um_nik

8. uwi

9. izban

10. SpyCheese

11. dreamoon_love_AA

12. ilyakor

13. chemthan

14. JOHNKRAM

15. eddy1021

Top 15 in India:

1. gvaibhav21

2. pranjal.ssh

3. Baba

4. yashChandnani

5. teja349

6. jtnydv25

7. ajinkya1p3

8. polingy

9. hitman623

10. GT_18

11. Equinox

12. sinus_070

13. Shivram

14. abisheka

15. nishant_coder

Hi all!

Soon thousands of people will participate in Google Code Jam qualification round. There is a problem though: Code Jam website doesn't offer a good place to discuss the problems afterwards. There is an official Google group, but it is a poor place for discussion: not only is it premoderated, but they also reject/delete useful posts, like this one.

There is a solution: point people at Codeforces, the best place to discuss programming competitions! If we just start posting messages about Codeforces to the Google group, they will probably delete them. But there is something else that people (sometimes) read: your code. For many years, Code Jam allowed anyone to read any participant's code after the contest. While the current system doesn't support this yet, this is something that Code Jam team is willing to resolve. So, my idea is for as many people as possible to add a comment like this to every Code Jam submission:

// Discuss this problem on Codeforces: http://mirror.codeforces.com/

Or better, use a link to a post about the specific round. This way, those who try to learn by looking at other's code will find out about Codeforces, which is good.

Do you have any similar ideas?

Hello, Codeforces.

In this post we want to talk about the Codeforces and Polygon improvements, which were implemented recently.

Blogs (Codeforces)

Previously, Codeforces blog posts can either be published together with the translation, or both versions can be hidden in drafts. Now a blog post can be published or hidden in drafts separately from its translation. In case there is a published post, and its translation is hidden in drafts, or in the opposite case, you will see a corresponding warning about that. Also the logic of the Recent Actions was completely revised.

Talks (Codeforces)

Also added a new functional in the Talks. For some users, it was inconvenient if a talk with one person contains a lot of messages. The page Dialogues has been implemented. It contains all the dialogs, sorted by the time of the last message. For each dialog, only one row with the last message is shown. When you click the message the talk with this person will open. When you open talk with the person, all messages sent to you by the corresponding person automatically become read. The old-style talks page is also fully preserved.

Hello Codeforces!

On April 04, 17:05 MSK Educational Codeforces Round 41 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 one day 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 Roman Roms Glazov, Adilbek adedalic Dalabaev and me.

We'd like to thank Mikhail awoo Piklayev and Ivan BledDest Androsov for the help in preparing the round.

Good luck to all participants!

UPD Editorial

UPD2

Congratulations to the winners:

Congratulations to the best hackers:

518 successful hacks and 491 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

Hello codeforces!

I'm glad to announce that codeforces round #473 for the second division will take place on Tuesday April 3rd 16:05 UTC. As usual, first division participants can take part out of competition.

I'm the problemsetter and the editorialist of this round. I'd like to thank mahmoudbadawy for creating the testdata and testing the round, FalseMirror, Livace, demon1999, and vintage_Vlad_Makeev for testing the round, KAN and Ahmad_Elsagheer for giving their great opinions and thoughts and helping in round preparation, arsor for helping translate the problems, and MikeMirzayanov for the great codeforces and polygon platforms.

You'll be given 6 problems and 2 hours to solve them.

UPD : the scoring distribution will be 500-1000-1250-1750-2000-2500.

UPD : Editorial and bonus tasks.

Good luck and Have fun!

UPD congratulations to the winners!

Div.1:-

1. Um_nik
2. dotorya
3. kmjp
4. natsugiri
5. Lewin

Div.2:-

1. StopBullying
2. taeyeon_ss
3. Tsuare
4. readers2
5. ajinkya1p3

The contest is over; I hope you've enjoyed it :-) Editorial is here.

The 6th April Fools Day Contest will take place on Sunday April 1st. This is a joke competition in which solving the problem is often easier than figuring out what the actual task is.

This year I tried to make the problems less puzzling and more versatile. For example, almost all problems have a statement! And you won't need OEIS this time :-)

In this round you'll be given 7 weird problems and 2 hours to solve them. The contest will use ACM ICPC rules (no hacks, the standings are decided by the number of solved problems and penalty time earned on them), and it will be unrated. You can submit solutions in any language allowed by Codeforces. To get an idea of what the contest will look like, you can check out the contests of the past years: 2012, 2013, 2014, 2016, 2017.

As usual, to enjoy competing in this round you'll need a sense of humor compatible with mine! Good luck, and have fun!