Hello, Codeforces!

Zlobober and I are glad to invite you to compete in Nebius Welcome Round (Div. 1 + Div. 2) that will start on 12.03.2023 17:35 (Московское время). The round will be rated for everyone and will feature 8 problems that you will have 2 hours to solve.

I feel really thrilled and excited about this round as this is the first time I put so much effort in a Codeforces contest since I quit being a round coordinator in December 2016 (wow, that was so long ago)!

We conduct this round to have some fun and we also hope to find some great candidates to join Nebius team. Solving 5+ problems in our round will be a good result and will count as one of the coding interviews. Apart from that top 25 contestants and 25 random contestants placed 26-200 will receive a branded Nebius t-shirt!

Some information about Nebius. I have joined this new start-up in cloud technologies in November as a head of Compute & Network Services. It's an international spin-off of Yandex cloud business with offices in Amsterdam, Belgrade and Tel Aviv. We offer strategic partnerships to leading companies around the world, empowering them to create their own local cloud hyperscaler platforms and become trustworthy providers of cloud services and technologies in their own regions.

We know that competitive programming makes great engineers. It boosts your algorithms and coding skills, teaches you to write a working and efficient code. We aim to hire a lot of backend software engineers for all parts of our cloud technology stack that ranges from hypervisor and network to data warehouse and machine learning.

Here you can check Nebius website and open positions. If you feel interested in joining Nebius as a full-time employee, go on and fill the form.

Special thanks go to:

• MikeMirzayanov for his outstanding, glorious, terrific (you can't say enough, really) platforms Codeforces and Polygon

• 74TrAkToR and KAN for this round coordination (and for rounds coordination in general, good job lads!)

• ch_egor for his help with one of the problem that has a peculiar setting which we will discuss a lot in the editorial

• UPD Now that the list is complete we can say many thanks to all the testers! dario2994, errorgorn, magga, golikovnik, Hyperbolic, Farhan132, IgorI, vintage_Vlad_Makeev, aymanrs, Vladik, Junco_dh, dshindov, csegura, Eddard, Alexdat2000, kLOLik, wuruzhao, Aleks5d, Ryougi-Shiki, qrort, ak2006, AsGreyWolf, farmerboy, vladukha, usernameson, segment_tea, DzumDzum, Java, samvel, qwexd, Tensei8869, thank you for all your help on improving this round's quality!

Fingers crossed all will be well, you will enjoy the round and we will be back with a new one in several months!

UPD2 The scoring distribution is 500 — 1000 — 1000 — 1500 — 2000 — 2750 — 3500 — 3500.

UPD3 The editorial is here!

UPD4 Congratulations to winners!

1-st place: jiangly

2-nd place: tourist

3-rd place: Um_nik

4-th place: isaf27

5-th place: Ormlis

UPD5 T-shirts winners!

Hello!

Right now happens the first tour of the Open Olympiad in Informatics, and tomorrow will be the second one. This contest is prepared by Moscow Olympiad Scientific Committee that you may know by Moscow Team Olympiad, Moscow Olympiad for Young Students and Metropolises Olympiad (rounds 327, 342, 345, 376, 401, 433, 441, 466, 469, 507, 516, 541, 545, 567, 583, 594, 622, 626, 657, 680, 704, 707, 727, 751, 775, 802, 829, 852).

Open Olympiad consists of the most interesting and hard problems that are proposed by a wide community of authors, so we decided to conduct a Codeforces regular round based on it, which will happen on Mar/09/2023 12:35 (Moscow time) and will be based on both days of the Olympiad. Note the unusual time of the round. Each division will have 7 problems and 3 hours to solve them.

We kindly ask all the community members that are going to participate in the competition to show sportsmanship by not trying to cheat in any manner, in particular, by trying to figure out problem statements from the onsite participants. If you end up knowing some of the problems of Moscow Open Olympiad (by participating in it, from some of the onsite contestants or in any other way), please do not participate in the round. We also ask onsite contestants to not discuss problems in public. Failure to comply with any of the rules above may result in a disqualification.

Problems of this competition were prepared by Mangooste, Artyom123, teraqqq, Ziware, vaaven, Tikhon228, Ormlis, Kirill22, ViktorSM, isaf27, DebNatkh and DishonoredRighteous guided by grphil and Helen Andreeva.

Thanks to Aleks5d for the round coordination, statement translation and preparation of problems for the second division, and also thanks for MikeMirzayanov for systems Codeforces and Polygon, which was used to prepare problems of this olympiad.

Good luck everybody!

Due to the official competition source codes of other participants will not be available for an hour after the end of the round.

UPD1: Please note the number of problems and the duration of the round have been increased for each of the divisions.

UPD2: Great thanks to the testers of the round: BucketPotato, valeriu, 4qqqq, Aaeria, FedeNQ, olya.masaeva! As well as the testers of the main Olympiad: Siberian, Maksim1744, sadovan, Kapt, Pechalka, alexxela12345, Be_dos, princebelkovetz, Jatana, KiruxaLight, cute_hater!

UPD3: Scoring distribution:

Div.2: 500 — 750 — 1250 — 1750 — 2000 — 2500 — 3500

Div.1: 500 — 1000 — 1250 — 1750 — 2500 — 3500 — 3500

UPD4: Editorial, we apologize for the delay:(

Hello everyone! The 7th Stage of the 1st Universal Cup: Zaporizhzhia, will be held on March 11th, 2023.

The contest is based on the Day 2: Oleksandr Kulkov Contest 3 from the Osijek Competitive Programming Camp 2023. Please, don't participate if you have seen these problems.

Authors of the problems: adamant, fedimser, I would also like to thank -is-this-fft- for the help with the preparation of the contest.

We hope you will like the problems!

You can participate in the contest in the following three time windows:

• Mar 11th 13:00 — 18:00 (UTC +8)
• Mar 11th 19:00 — 24:00 (UTC +8)
• Mar 12th 02:00 — 07:00 (UTC +8)

Please note that you can see two scoreboards in DOMjudge. The 'Local Scoreboard' shows the standings ONLY IN THE CURRENT TIME WINDOW. And the 'Combined Scoreboard' shows all participants, including the onsite participants, and the cup participants in the previous time windows.

Contest link: https://domjudge.qoj.ac/

Universal Cup Scoreboard: https://qoj.ac/ucup/scoreboard

About Universal Cup:

Universal Cup is a non-profit organization dedicated to providing trainings for competitive programming teams. Up to now, there are more than 200 teams from all over the world registering for Universal Cup.

A more detailed introduction: https://codeforces.net/blog/entry/111672

Register a new team: https://ucup.ac/register

Hola Codeforces!

I am happy to invite you to Codeforces Round 856 (Div. 2), which will take place on Mar/04/2023 20:35 (Moscow time). Notice the unusual time! The round will be rated for participants with rating lower than 2100. You will have 2 hours to solve 5 problems. The problems were authored and prepared by me.

I would like to thank the following people who made the round possible:

• pashka for coordination, help in problem preparation and translating the statements.
• errorgorn, mjhun, BucketPotato, darkkcyan, MarcosK, CodigoL, perdu, AngrySeal, SebaMarin, Crazypy, CarusoX, alwyn, khangai11, byakko, rchaves, pizzaroot, YOK, rekomodo, helcsnewsxd, AEBOV and EyadBT for testing and providing valuable feedback.
• MikeMirzayanov for the great Codeforces and Polygon platforms.

See you in the standings!

UPD:

Scoring distribution: $$$750$$$ — $$$1000$$$ — $$$1250$$$ — $$$2000$$$ — $$$2750$$$

UPD: Editorial

UPD: Congratulations to the winners!

Official winners:

1. lunchbox
2. Meaf
3. 14th_onresp
4. kalimm
5. izhang

Unofficial winners:

1. jiangly
2. maspy
3. neal
4. potato167
5. arvindf232

Hello! Codeforces Round 855 (Div. 3) will start at Mar/02/2023 17:35 (Moscow time). You will be offered 6-8 problems 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 a rating of 1600 or higher, can 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.

You will be given 6-8 problems and 2 hours and 15 minutes to solve them.

Note that the penalty for the wrong submission in this round 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 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.

Thanks to MikeMirzayanov for the platform, help with ideas for problems and for coordination of our work. Problems have been created and written by ITMO University team: MikeMirzayanov, myav, Aris, Gornak40, senjougaharin and Vladosiya.

We would like to thank: tolbi, lunchbox, Son, sary, Wibo, yorky, nigus, tute7627, 74TrAkToR, bigfoot19982, oversolver, Be_dos, CARBINE, molney, KoT_OsKaR, Nickir, cute_hater, Crutch, vrintle, Rubikun, akulenok, medk, Jostic11, Ghassane for testing the contest and valuable feedback. List of testers will be updated.

Good luck!

UPD: Editorial

Hello Codeforces!

On Feb/28/2023 17:35 (Moscow time) Educational Codeforces Round 144 (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 or 7 problems and 2 hours to solve them.

The problems were invented and prepared by 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!

UPD: Editorial is out

Hello, Codeforces!

It is the last call to register for the 2nd “Hello Muscat 2023” ICPC programming bootcamp, the continuation of the “Hello” bootcamp series, organised by Harbour.Space University, in collaboration with PhazeRo, Gutech, UK Oman Digital Club, Leagues of Code, Gutech CS Club and Codeforces!

We are inviting all of you to join us from March 8th to March 16th, 2023 in Muscat, Oman for an intense 8 days of programming! It is not only a great opportunity to train but also a chance to discover a new amazing country. March is an especially great time to visit Oman if you want to enjoy nice beach weather — don’t miss it!

As always, we can’t wait to see you there to learn, practice and compete on the international stage, smoothing your road towards the joined World Finals 2022 and 2023 in Egypt!

Our coaching line-up combines talent and experience, featuring ICPC world champions winners and finalists, as well as legendary names from the field of competitive programming: Mike Mirzayanov MikeMirzayanov, Yahor Dubovik 244mhq, Artem Plotkin Rox, Maksym Oboznyi MaksymOboznyi, Gleb Evstropov GlebsHP and Nikolay Budin budalnik.

It will be an amazing opportunity for teams from all over the world to learn from these well-known and successful coaches in the ICPC world!

The Bootcamp will be split into three divisions:

• Division A. Division A will be a mirror of the Petrozavodsk Programming Camp. Suitable for teams who already qualified for the world finals ICPC or are aiming that high.

• Division B. Designed to help teams prepare for the next season of ICPC regional competitions.

• Division C. Designed for newcomers to the world of ICPC competitive programming. For those with a handle on the basics but want to compete in future regional competitions, this division is the perfect starting point.

Tentative Schedule:

*Topic will be decided based on participants’ levels

**Schedule time is in GMT+4

Types of participation: On-Site and Online

We believe that participation in our Bootcamp should be accessible by all teams wherever they are and that is why we made onsite and online types of participation.

Full Scholarships Available: Online

We are delighted to invite all the recent medalists, eligible finalists and teams ICPC, IOI and IMO 2022 and 2023 to join our Bootcamp for FREE online. Please register using a promo code IOI_IMO_ICPC_FINALIST. Note that we will ask for proof of your full scholarship eligibility. On a case by case basis we may also consider granting full scholarship to Codeforces members with rating above 2200 (promo code — CF2200), do not hesitate to apply!

Standard Participation Fees:

Daily schedule: On-Site and Online

On-site

Online

You can ask any questions by email: [email protected]

Hi!

This round is sponsored by esports team cybercats. The team was founded in October 2021 by me and subscriber.

We currently have a Dota 2 roster, playing in the second division of EEU DPC. Come support us on streams and in the comments!

As a thank you to Codeforces and the competitive programming community, we decided to make this round and give away 100 plush cybercats!

The prizes will be awarded to the first 100 places in the round.

Follow our social networks:

   (RU) VK    (RU) telegram    (RU) youtube    (EN) twitter.

The problem set was prepared by subscriber, isaf27, KAN, Catmoonlight, jdurie and BucketPotato.

Round was tested by enot110, izban, qwerty787788, MateoCV, ilyakrasnovv, blobugh, ak2006, Valters07, DiegoGarcia, Chaska, kzyKT, Dan4Life, FedeNQ, alysonNBS, petertromso and jojonicho.

UPD. Scoring distribution: 500 — 1000 — 1500 — (1500 — 750) — 2250 — 2500 — 3000 — 3500.

UPD. editorial

UPD: The start time has been changed. Note that the start time is unusual.

Hi Codeforces!

Bazoka13, Toxel, and I Serval are glad to invite everyone to participate in Codeforces Round 853 (Div. 2), which will be held on Feb/25/2023 17:20 (Moscow time).

This round will be rated for participants with rating lower than 2100. We will be glad to see the participants with a higher rating to take part in our round unofficially as well!

You will be given 6 problems to solve in 2 hours. Scoring distribution will be announced later.

We would like to thank everyone that makes this round possible:

• Artyom123 for coordination of the round and help with the preparation.
• SSerxhs, skywalkert, zlc1114, foreverlasting, tiger2005, OMG_link, fried-chicken, tibinyte, _Viole_, qxforever, sleep__, valeriu, Nanako, HomuraCat, AntiLeaf, rsj, tyakennikku, qsmcgogo, Lanly, Dominater069, GGN_2015, Kumiko, StudyingFather, ClearQwQ and Ben_H for testing the round and providing valuable feedbacks.
• MikeMirzayanov for the amazing Codeforces and Polygon platforms.
• You, for participating in the round.

Good luck & Have fun! :P

UPD2: Scoring distribution: 500 — 1000 — 1250 — 1750 — 2000 — 2750.

UPD3: Editorial is out. Thanks for your participation!

Congratulations to the winners!

Overall:

1. daubi
2. BurnedChicken
3. maspy
4. tute7627
5. Um_nik

Div. 2:

1. MakaPakka
2. inhabitant
3. b8LI
4. Reisael
5. stkwill