Hello, Codeforces!

I invite you to participate in Codeforces Round 931 (Div. 2), which will be held on Mar/01/2024 17:35 (Moscow time).

The round will be rated for participants with rating lower than 2100. Participants with higher rating can participate in round unofficially.

You will have 2 hours to solve 5 problems, with one of the problems having 2 versions. One or more interactive problems may occur in the round, so please read guide for interactive problems before the contest.

All problems are authored by me.

I would like to thank:

• Akulyat for round coordination and help with preparation

• A_G, okwedook, rui_er, jdurie, lunchbox, _rey, wjli, .-O_O-., aryanc403, akshaykhandelwal, PartTimeCoder, carnation13, its_pranjal_83, Ianlsam, Immerser, vikram108, praneeth6116, soham976roy, and Dev_30 for testing the round and providing useful feedback.

• MikeMirzayanov for Codeforces and Polygon platforms.

Good luck to all participants!

UPD: Score distribution: 500 — 1000 — 1500 — (1500 — 1250) — 3250

UPD2: Editorial

UPD3: Congratulations to the winners!

Div1 + Div2

Div2

"You are braver than you believe, stronger than you seem, and smarter than you think." — A.A. Milne

Hello Codeforces!

I have the pleasure of inviting you to participate in Codeforces Round 930 (Div. 1) and Codeforces Round 930 (Div. 2), which will start on Feb/29/2024 17:35 (Moscow time).

You will be given 6 problems and 2 hours to solve them in both divisions.

One of the problems may be interactive. So, please refer to the guide on interactive problems if you are unfamiliar with them.

The problems were prepared and authored by wuhudsm, chromate00, Psychotic_D and MagicalFlower.

We would like to thank :

• irkstepanov for coordinating the round;
• BurnedChicken for the only LGM testing;
• amenotiomoi,siganai, vgtcross, amethyst0, dognotlike, alireza_kaviani, and dorijanlendvaj for GM and IGM testing;
• aryanc403, k1r1t0, Little_Sheep_Yawn, Amir_Parsa, blxst, pavlekn, Error_Yuan, IceKnight1093, aufannn, Mingyu331, Akulyat, Arpa, and mhtkrag for M and IM testing;
• O--O, Abhishek_Srivastava, MrDelrus, htetgm, Silver_Fox, dhyang24, and milind0110 for CM testing;
• brave-kid, adventofcode, vikram108, mafailure, AnanasClassic, Yugandhar_Master, FD..LH..lloyJ, lemoncookie, and flakes24 for Expert testing;
• Banis, stepan.karpov, BF_OF_Priety, and ONEHUNDREDPUSHUPS for Specialist testing;
• HexShift for the only Pupil testing;
• JaberSH1 for the Newbie testing;
• tibinyte for the Illegal newbie lying face testing;
• MikeMirzayanov for the great Codeforces and Polygon platforms;
• And at last but not least, You for participating in the round!

Good luck, and may the code be with you!

UPD: Score distribution:

Div.1: $$$500 - 1000 - 1500 - 2000 - 2500 - 2750$$$

Div.2: $$$500 - 1000 - 1500 - 2000 - 2500 - 3250$$$

UPD2: Let's continue the streak of announcements with photos of the authors and coordinator.

UPD3: Editorial is out.

UPD4: Top Performers

Div.1

Div.2

“It is not important to be better than someone else, but to be better than you were yesterday.” — Master Oogway, Kung Fu Panda

Hello, Codeforces! We are proud to present Codeforces Round 929 (Div. 3), and we hereby invite all of you to take part in it. This round will start on Feb/27/2024 17:35 (Moscow time). You will have 2 hours and 15 minutes to solve 7 problems. The penalty for a wrong submission is equal to 10 minutes.

This round will be rated for participants with ratings lower than 1600. However, all of you who wish to take part and have a rating of 1600 or higher, are welcome to register for the round unofficially.

The round will be hosted by rules of educational rounds (extended ICPC). Thus, solutions will be judged on preliminary tests during the round, and after the round, it will be a 12-hour phase of open hacks.

Remember that only the trusted participants of the third division will be included in the official standings table. As stated in this blog, this is a compulsory measure for combating unsporting behaviour and upholding gracious professionalism. To qualify as a trusted participant of the third division, you must:

• take part in at least five 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.

The problems were authored and prepared by erniepsycholone, snowysecret, dbsbs, jerryliuhkg, lomienyeet, and our beloved coordinator Vladosiya.

We would like to thank:

• Vladosiya for his high-speed coordination;

• arvindf232 for Legendary Grandmaster testing;

• step_by_step for International Grandmaster testing;

• physics0523, culver0412, AHappyPotato for Grandmaster testing;

• pavlekn for Master testing;

• moonpie24, anthony123, mariowong123 for Candidate Master testing;

• peshkoff, ksodp, SashaT9, Elison, MoLotfi for Expert testing;

• DBSHoShunNgai, Doncho_Bonboncho for Specialist testing;

• myvaluska, dbsMarco, dbsptl for Pupil testing;

• CannotPupil, KyleLeungHS for Newbie testing;

• MikeMirzayanov for creating Codeforces and Polygon.

We hope that this contest, regardless of your background, rating and result, will increase your exposure to competitive programming and make you better than you were yesterday. Have fun!

UPD: Let's continue the streak of announcements with photos of the authors. This time with our coordinator and testers :)

UPD2: We discovered the screencast from Um_nik a short while before the end of the contest, and it had around 400 views by the end of the contest. Round is still rated, however, people who have used his solutions will be punished.

UPD3: Editorial is out

Hello Codeforces!

On Feb/23/2024 17:35 (Moscow time) Educational Codeforces Round 162 (Rated for Div. 2) will start.

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 or 7 problems and 2 hours to solve them.

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

Good luck to all the participants!

UPD: Editorial is out

mesanu, SlavicG and I are very excited to invite you to Codeforces Round 928 (Div. 4)! It starts on Feb/19/2024 17:35 (Moscow time). We would also like to give a very special thanks to the efforts of MikeMirzayanov and Vladosiya, who helped significantly with the preparation of the round!

The format of the event will be identical to Div. 3 rounds:

• 5-8 tasks;
• ICPC rules with a penalty of 10 minutes for an incorrect submission;
• 12-hour phase of open hacks after the end of the round (hacks do not give additional points)
• after the end of the open hacking phase, all solutions will be tested on the updated set of tests, and the ratings recalculated
• by default, only "trusted" participants are shown in the results table (but the rating will be recalculated for all with initial ratings less than 1400 or you are an unrated participant/newcomer).

We urge participants whose rating is 1400+ not to register new accounts for the purpose of narcissism but to take part unofficially. Please do not spoil the contest for the official participants.

Only trusted participants of the fourth division will be included in the official standings table. This is a forced measure for combating unsporting behavior. To qualify as a trusted participant of the fourth division, you must:

• take part in at least five rated rounds (and solve at least one problem in each of them),
• do not have a point of 1400 or higher in the rating.

Regardless of whether you are a trusted participant of the fourth division or not, if your rating is less than 1400 (or you are a newcomer/unrated), then the round will be rated for you.

Thanks a lot to the testers: MADE_IN_HEAVEN, Gheal, Dominater069, Phantom_Performer, Vladosiya, htetgm, hbarp, tvladm!

We suggest reading all of the problems and hope you will find them interesting. Good luck!

UPD: Editorial is posted!

Hello! On 18.02.2024 15:05 (Московское время) will start Codeforces Round 927 (Div. 3), the next Codeforces round for the third division.

The round is based on problems from JetBrains Academy Youth Challenge. If you participated in it, please don't participate in this round.

Problems for this round are prepared by denk, step_by_step, goncharovmike, ikrpprppp, pashka, Vladosiya and MikeMirzayanov.

Thank you very much awoo, BledDest, buyolitsez, EgorUlin, Gojova, GrandFruit, Hello_zoka, petyb, scanhex, senjougaharin, shnirelman, SomethingNew, Toy_mouse, Zandler for testing the round.

As usual for the third division rounds:

• there will be 6-8 tasks in a round
• round duration is 2 hours 15 minutes
• the round follows the ICPC rules, penalty for an incorrect submission is 10 minutes
• round is rated for participants with ratings up to 1600
• after the round there will be a 12-hour open hacking phase

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 behaviour. To qualify as a trusted participant of the third division, you must:

• take part in at least five 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.

Good luck to all!

UPD: Editorial

Hello, Codeforces!

Welcome to the think-cell Round 1 supported by think-cell, which will start on Feb/17/2024 17:35 (Moscow time). It will be a combined rated round for both divisions. All problems were authored and prepared by Elegia and satyam343.

We would like to thank:

• errorgorn for round coordination and help with preparation
• KAN for helping with the preparation of problems
• Alexdat2000 for Russian translation
• GoatTamer and Non-origination for discussing problems with us while our proposal was in review and testing the round.
• Kaitokid, antekb, vgtcross, riano_, mtw, AboAbdoMC, Vladithur, BERNARD, milind0110, conqueror_of_tourist, Um_nik, gamegame, htetgm, brobat, LucaLucaM, the_hyp0cr1t3, tibinyte, 18o3, ExpensiveAC, MateiKing80, udhavvarma03, Non-origination, RDDCCD, Kuroni, Brovko, LipArcanjo, andrei_boaca, nok0, oursaco, ffao, prvocislo, SmolBrain, dario2994, brunovsky, tabr, PurpleCrayon, IceKnight1093, aryanc403 and Golovanov399 for testing the round
• MikeMirzayanov for great systems Codeforces and Polygon.

You will be given $$$9$$$ problems and $$$3$$$ hours to solve them. One of the problems will be divided into two subtasks. One of the problems will be interactive. Make sure to read this blog and familiarize yourself with these types of problems before the round!

We hope you'll like the problemset!

UPD 1 : The score distribution is $$$500 - 1000 - 1500 - (1250 + 1000) - 2500 - 2750 - 3500 - 3500 - 5000$$$.

Congratulations to the winners!

1. cnnfls_csy

2. Geothermal

3. Benq

4. gyh20

5. Ormlis

6. jiangly

7. tourist

8. ksun48

9. Petr

10. maroonrk

Congratulations to the first solves as well!

• A : SSerxhs

• B : SSerxhs

• C : M_A

• D1 : hitonanode

• D2 : hitonanode

• E : ksun48

• F : MAOooOAM

• G : gyh20

• H : maroonrk

• I : Kapt [upsolved]

UPD 2: Editorial is out.

And now a word from our round partner – think-cell:

think-cell is the leading data visualization software for business presentations. Our mission is to offer the most intuitive user interface for generating complex data-driven charts and slides, while at the same time ensuring seamless integration with Microsoft Office. We work on challenging visualization problems, reverse-engineer Microsoft’s code, and reinvent how slides are created. think-cell is the only German company funding the C++ ISO committee delegation, so there is a good chance that components we invent will find their way into the standard.

Right now, we are looking for smart, creative C++ engineers with a solid theoretical background to join our engineering team.

Highlights of the role:

• We use the latest C++ features as soon as the compilers support them.
• We’re not afraid of advanced template metaprogramming or macros when they avoid code duplication or lead to cleaner, more readable code.
• We prefer algorithms and ranges (esp. ours!) over raw loops.
• We take the time to deliver perfect code.
• We love refactoring and modernizing old code and introducing our own libraries.
• If we can do better than the standard library, we write our own!
• If we have done something cool, we talk about it at C++ conferences.
• If we are missing a C++ language feature, we write a proposal and present it to the C++ standard committee.

Here is what we offer:

• A competitive salary from the start and a raise to EUR 130,000 annually after only one year.
• Full support with relocation to Berlin or the option to work fully remotely.
• An apartment for the first month if relocating to Berlin.
• Lifestyle-friendly working hours, no deadlines, no overtime.
• No scheduled meetings.
• An international team of brilliant minds.
• A flat organisation with respectful colleagues and plenty of room for your ideas.
• A working environment that is driven by the strive for excellence.

Already convinced?

P.S. don't forget to check out our developer blog to learn more about our commitment to the tech world!

Join think-cell Round 1 that will start on Feb/17/2024 17:35 (Moscow time) for a chance to challenge your skills among other developers and win the following prizes.

- First place: Apple iPad Air (10.9-inch iPad Air Wi-Fi 256GB),
- Second and Third place: Apple Watch (Apple Watch Series 9 GPS + Cellular, 41mm Aluminum Case with Solo Loop),
- 4-50 places: think-cell branded socks
- 200 additional socks will be distributed randomly among the rest of the participants who solved at least one problem and for whom this is not the first rated round!

Neko Nya, Кодефорсес =＾● ⋏ ●＾=

I'm happy to invite you to participate in Codeforces Round 926 (Div. 2). It will take place on Feb/15/2024 17:35 (Moscow time) and in it, you will help a boy named Sasha win over a girl's heart. The round will be rated for all participants with a rating strictly less than 2100. You will have 2 hours to solve 6 problems.

Here is a big thank you to everyone involved in the round:

• The cutest coordinator Artyom123. (No offense to the others)
• KAN, geranazavr555, MikeMirzayanov for the BEST platform.
• Legion of testers: A_G, AgafonovArtem, Alexdat2000, Vladithur, wuhudsm, petyb, induk_v_tsiane, sevlll777, mz1, SomethingNew, AVdovin, NewLul, damirsit, skylak3_3, Andreasyan.
• Also to this wonderful person for his invaluable contribution to the round teraqqq.

Looking forward to seeing everyone at the contest >~<

UPD: Scoring distribution: 500 — 1000 — 1500 — 2000 — 2500 — 3000

UPD2: Editorial

Dear Codeforces,

I am honored to share that the X-th edition of the AGM International Programming Contest has officially begun!

AGM is addressed to High School students who compete in teams of up to 3 members, ICPC-style. The contest has 2 rounds:

1. The Qualification Round held online, on Saturday, the 23rd of March 2024 between 14:00 and 19:00 GMT+2 (timeanddate)
2. The Final Round held onsite in Bucharest. The date and time will be announced soon.

Registrations are opened until the 20th of March at 17:00 GMT+2: https://forms.gle/WbS4zjsJhBaXmjYHA

The problem sets are entirely developed by current and former university students from the United Kingdom and Romania.

The top 10 teams of the Final Round will receive Diplomas. Additionally, the top 3 teams of the Final Round will receive cash prizes:

• I-st place: 1200 RON
• II-nd place: 900 RON
• III-rd place: 600 RON

In the meantime, please have a look over the last four years' problem sets here.

Here are some useful links:

• Website: https://agm-contest.com
• Facebook: @AGM.Contest
• Competition Rules: https://agm-contest.com/competition-rules
• E-mail address: [email protected]

Finally, I am more than delighted to present our team: patrick.sava (the heart of the project), teoionescu, carabet.cosmin, Mihai22e, Stelutzu, munteanuvlad98, caesar2001, average_frog_enjoyer, popovicirobert, Alex18mai, ionan6ix, butasebi, Stefan_Radu, eman98, mihaicristian, yodoli27, cristb, venom1724, zarg169 and me

We are looking forward to welcoming everyone!

Kind regards,

George