Hello, Codeforces!

First and foremost, we would like to say a massive thank you to everyone who entered and submitted their answers to the first Kotlin Heroes competition which was held back in May. Congratulations to the top 3 winners Petr, ecnerwala, and eatmore on their incredible achievement, especially considering they were up against 4,500 other registrants from over 63 countries. We’d also like to give a shout out to tourist for being the only other person, outside of the top 3, to manage to solve every problem set from this round. Well done all of you!

Ready to challenge yourself to do better? The second "Kotlin Heroes" competition will be hosted on the Codeforces platform on the 7th of September, 2019, at 14:35 UTC (17:35 MSK, 07:35 PDT, 22:35 CST). The contest will last 2 hours 30 minutes and will feature a set of problems from simple ones, designed to be solvable by anyone, to hard ones, to make it interesting for seasoned competitive programmers. Top three winners will get prizes of $512, $256, and $128 respectively, top 50 will win a Kotlin Heroes t-shirt and an exclusive Kotlin badge, competitors solving at least one problem will enter into a draw for one of 50 Kotlin Heroes t-shirts.

The round will again be held in accordance with a set of slightly modified ICPC rules:

• The round is unrated.
• The contest will have 6-10 problems of various levels of complexity.
• You are only allowed to use Kotlin to solve these problems.
• Participants are ranked according to the number of correctly solved problems. Ties are resolved based on the lowest total penalty time for all problems, which is computed as follows. For each solved problem, a penalty is set to the submission time of that problem (the time since the start of the contest). An extra penalty of 10 minutes is added for each failed submission on solved problems (i.e., if you never solve the problem, you will not be penalized for trying that problem). If two participants solved the same number of problems and scored the same penalty, then those of them who had previously made the last successful submission will be given an advantage in the distribution of prizes and gifts.

Registration is already open and available via the link. It will be available until the end of the round.

If you are still new to Kotlin we have prepared a tutorial on competitive programming in Kotlin and a practice round, where you can try to solve a few simple problems in Kotlin. All the solutions are open, which means that you can look at the solution even if you haven't solved the problem yet. The practice round is available by the link.

We wish you luck and hope you enjoy Kotlin.

UPD: Thank you for the participation. The editorials are published.

Hello Codeforces!

On Sep/05/2019 17:35 (Moscow time) Educational Codeforces Round 72 (Rated for Div. 2) 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 the participants with rating lower than 2100. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. 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 6 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, Adilbek adedalic Dalabaev, Vladimir vovuh Petrov, Ivan BledDest Androsov, Maksim Neon Mescheryakov and me. Also huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all the participants!

Our friends at Harbour.Space also have a message for you:

Hello Codeforces,

Harbour.Space University and UTCC are collaborating to offer graduate students from anywhere in the world a once in a lifetime opportunity: fully funded scholarships for our Masters programs in Bangkok.

These scholarships are designed to completely eliminate the barrier between exceptional talents and sophisticated education: they cover the entire tuition fee as well as the cost of living expenses, and furthermore, they provide the student the valuable experience of both studying and working at Harbour.Space University.

We’re looking for the people who are going to change the world.

If you or someone you know are interested in technology, entrepreneurship, or design, and believe you have what it takes, we want to hear from you!

Congratulations to the winners:

Congratulations to the best hackers:

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

UPD: The editorial is out

Hi everybody!

These days Moscow is conducting the 4th International Olympiad of Metropolises that is an international competition for high school students from biggest cities and capitals all around the world. One of the disciplines of the competition is informatics. Rounds of the competition were prepared by the jury members invited from St. Petersburg, Minsk, Belgrade and Moscow olympiad scientific committee which you may know by Moscow team Olympiad, Open Olympiad in Informatics and Moscow Olympiad for young students (rounds 327, 342, 345, 376, 401, 433, 441, 466, 469, 507, 516, 541, 545, 567).

Scientific Committee of the olympiad consists of: Chmel_Tolstiy, Jelena Hadži-Purić, Elena Andreeva, Zlobober, GlebsHP, andrewzta, meshanya.

The problems were developed by isaf27, cdkrot, manoprenko, GoToCoding, ch_egor, vintage_Vlad_Makeev, voidmax, grphil, malcolm under the guidance of GlebsHP and Zlobober.

Problems were adapted for codeforces by vintage_Vlad_Makeev and cdkrot, also thanks for MikeMirzayanov for systems codeforces and polygon, which was used to prepare problems of this olympiad. Also, thanks LHiC, voidmax and wrg0ababd for testing!

Good luck and high ratings for everybody!

Round will happen on Sep/04/2019 12:05 (Moscow time) and will last for two and half hours.

The round will consist of 8 problems and will be combined for both divisions. The round is rated for all participants.

P.S. We kindly ask everybody who knows problems of an onsite event not to participate in a round and not to discuss them in public, as this may be a subject for disqualification.

UPD1: Winners!

1. EvenImage
2. gina0605
3. never_giveup
4. Radewoosh
5. 244mhq
6. cz_yixuanxu
7. ko_osaga
8. mango_lassi
9. GoForIt
10. ksun48

Editorial will be published soon.

UPD2: Editorial

<almost-copy-pasted-part>

Hello! Codeforces Round 582 (Div. 3) will start at Aug/30/2019 17:35 (Moscow time). You will be offered 6 or 7 problems (or 8) with expected difficulties to compose an interesting competition for participants with ratings up to 1600. However, all of you who wish to take part and have rating 1600 or higher, can register for the round unofficially.

The round will be hosted by rules of educational rounds (extended ACM-ICPC). Thus, during the round, solutions will be judged on preliminary tests, and after the round it will be a 12-hour phase of open hacks. I tried to make strong tests — just like you will be upset if many solutions fail after the contest is over.

You will be given 6 or 7 (or 8) problems and 2 hours to solve them.

Note that the penalty for the wrong submission in this round (and the following Div. 3 rounds) is 10 minutes.

Remember that only the trusted participants of the third division will be included in the official standings table. As it is written by link, this is a compulsory measure for combating unsporting behavior. To qualify as a trusted participants of the third division, you must:

• take part in at least two rated rounds (and solve at least one problem in each of them),
• do not have a point of 1900 or higher in the rating.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you.

Thanks to MikeMirzayanov for the platform, help with ideas for problems and for coordination of my work. Thanks to my good friends Mikhail awoo Piklyaev, Maksim Neon Mescheryakov and Ivan BledDest Androsov for help in round preparation and testing the round.

Good luck!

I also would like to say that participants who will submit wrong solutions on purpose and hack them afterwards (example) will not be shown in the hacking leaders table.

</almost-copy-pasted-part>

UPD: Thanks to Artem Rox Plotkin for testing the round!

UPD2: Editorial is published!

Hello Codeforces!

I would like to invite you to Manthan, Codefest'19, which will take place on Sunday, August 25, 2019 at 8:05 PM IST. This is a combined Div. 1 + Div. 2 round and is rated for participants from both divisions.

The Department of Computer Science and Engineering, IIT (BHU) is conducting Codefest from 23rd August — 25th August. Manthan, the algorithmic programming contest under the banner of Codefest, is being held as a special Codeforces round. The round follows regular Codeforces rules.

All problems in this round were created and prepared by drastogi21, _shanky, Enigma27, _hiccup, KAN and me (hitman623).

A lot of thanks to KAN, 300iq, vintage_Vlad_Makeev, _overrated_, Rox for the testing and valuable comments, and to MikeMirzayanov for the awesome Codeforces and Polygon platforms!

Prizes -

• 1st place — INR 25,000

• 2nd place — INR 18,000

• 3rd place — INR 12,000

• 1st place in India — INR 6,000

• 1st place in IIT(BHU) — INR 3,000

• 1st place among freshers (1st/2nd Year) of IIT(BHU) — INR 1,000

• Codeforces T-shirts to the participants who will be the first to solve each problem.

Participants will be offered 8 problems and 2 hours to solve them. As usual, the scoring distribution will be announced later.

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

UPD: The scoring is 500 — 1000 — 1500 — 2000 — 2250 — 2500 — 3000 — 3750

UPD: The contest has ended. Congratulations to the winners.

1. tourist

2. Um_nik

3. EvenImage

First place in India: cerberus97

Following are the participants who were the first to solve each problem and have won a Codeforces T-shirt. Congrats!

A. IgorI

B. Geothermal

C. icecuber

D. ILoLy

E. nocriz

F. GoGooLi

G. EvenImage

H. tourist

UPD: We decided to give the 8th T-shirt to IgorI for problem A. Congrats!

The editorial has been published.

Hope to see you next year!

Hello Codeforces!

On Aug/22/2019 17:35 (Moscow time) Educational Codeforces Round 71 (Rated for Div. 2) 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 the participants with rating lower than 2100. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. 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 invented and prepared by Roman Roms Glazov, Adilbek adedalic Dalabaev, Vladimir vovuh Petrov, Ivan BledDest Androsov, Maksim Neon Mescheryakov and me. Also huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all participants!

UPD: Our friends at Harbour.Space also have a message for you:

Hello Codeforces,

We are opening a new campus in Bangkok, Thailand!

We are delighted to introduce a strategic partnership between Harbour.Space University and the University of the Thai Chamber of Commerce – a collaborative effort powered by B.Grimm.

After 3 years of successfully disrupting education in Barcelona, with a unique educational model founded on active learning in entrepreneurship, technology, and design, as well as the most extraordinary academic and professional community on the planet to show for it, we are ready to bring the revolution to our new campus in Bangkok, Thailand.

Scholarships for our Bangkok campus are designed to completely eliminate the barrier between exceptional talents and sophisticated education: they cover the entire tuition fee as well as the cost of living expenses, and furthermore, they provide the student the valuable experience of both studying and working at Harbour.Space University.

Unique opportunities reserved for the most brilliant students from anywhere in the world, our scholarships are more than financial support – they are portals from your past to your future.

If you are graduating or have already completed a bachelor's degree, we are waiting for your applications for fully-funded Master's degree scholarships by the link below.

Congratulations to the winners:

467 successful hacks and 688 unsuccessful hacks were made in total!

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

UPD: Editorial is out

Hello! Codeforces Round 581 (Div. 2) will start on Aug/20/2019 17:35 (Moscow time). The round is rated for everyone whose rating isn't greater than 2099.

The problems were invented and prepared for you by rotavirus, rotavirus and rotavirus. Thanks to Anton arsijo Tsypko for the coordinating the round. Thanks to the testers for testing and giving advice:

• Ariel Ari Garcia;
• Anton antontrygubO_o Trygub;
• Mikhail awoo Piklyaev;
• Mriganka Basu mbrc Roy Chowdhury;
• Tiago Figueiredo tfg Gonçalves;
• Noam Noam527 Gutterman;
• Stefan stefdasca Dascalescu;
• Khaleel Adhami Al-Adhami;
• Rahul Rahul Goswami;
• Mohamed Bakry Ahmed;
• an incognito tester;
• Bencil BencilSharpeniro Sharpeniro;
• Luca average_frog_enjoyer Seritan;
• Alexey dalex Dergunov;
• Zain Zain Alabedeen Ali.
• gamegame

You will be given 5 problems and 2 hours to solve them. The score distribution will be announced later is 500-750-1250-(1500+750)-2500.

The round is over! Congratulations to the winners:
1. 79brue
2. sinus_070
3. baluteshih
4. weishenme
5. shahaliali1382

An editorial.

Hello again, Codeforces!

I am glad to invite you to Codeforces Round 580, which will take place on Aug/18/2019 16:45 (Moscow time). Round will be rated for both divisions.

All problems in this round were created and prepared by me, antontrygubO_o. I tried to make them interesting and hope that you will enjoy them!

A lot of thanks to arsijo for the excellent coordination of the round, 244mhq, gepardo, danya.smelskiy, reeWorld, Xellos, Mediocrity, I_love_tigersugar, KAN for the testing and valuable comments, and to Mike MikeMirzayanov Mirzayanov for the amazing platforms Codeforces и Polygon.

Participants in each division will be offered 6 problems and 2 hours 10 minutes to solve them. As usual, I strongly recommend reading statements of all problems!

I wish you good luck and high rating!

UPD1:

Scoring distribution of Div $$$2$$$ round: 500 — 1000 — 1500 — 1750 — 2250 — 3000

Scoring distribution of Div $$$1$$$ round: 500 — 750 — 1250 — 2000 — 2500 — 3000

UPD2:Editorial

UPD3 Congrats to winners!

Div 1:

1. TLE

2. Um_nik

3. mnbvmar

4. Benq

5. heuristica

Div 2:

1. kkkkk11

2. sucuk

3. ujrepacul

4. zzffxx

5. VahitGuetta

Hello!

We are very pleased to cooperate with XTX Markets, thanks to whom we are able to hold the Global rounds. Four of the six of them are already passed and here are the current results.

In short, XTX Markets is a leading quantitative-driven electronic market maker Launched in 2015, XTX Markets has rapidly become the number 1 FX spot liquidity provider by volumes globally, surging ahead of global banks.

Thanks for supporting our community!

We are happy to announce that XTX recently launched the XTX Markets Global Forecasting Challenge, powered by Correlation One.

The XTX Markets Global Forecasting Challenge is an online competition for aspiring quantitative professionals, where contestants are tasked to develop a predictive model based on training data provided by XTX.

Competition highlights include:

• Over $100,000 in total cash prizes.
• $7,500 for the best submission from a participant aged under-25 (as of 1st July 2019).
• Exciting job opportunities in London.
• Opportunity to compete against the best quantitative minds from around the world.

The competition is open to all data-minded contestants from 1st of July to 30th of September, 2019.

To get started, please sign up below.

We hope you'd be interested!