Hello Codeforces!

mesanu, flamestorm and I are very excited to invite you to Codeforces Round 859 (Div. 4)! It starts on Mar/19/2023 17:55 (Moscow time).

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.

Many thanks to all testers: jampm, Max_Calincu, KrowSavcik, TimaDegt, nyaruhodo, tibinyte, badlad, Phantom_Performer, AlperenT, Bakry, keta_tsimakuridze, Gheal, RedstoneGamer22, Dominater069!

And thanks to Alexdat2000 for translating the statements!

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

Good Luck to everyone!

UPD: Editorial

Hi Codeforces!

Talaodi, YunQian, xukai and I mazihang2022 are excited to invite everyone to participate in Codeforces Round 858 (Div. 2), which will be held on 18.03.2023 15:05 (Московское время). Please note the unusual start time.

This round will be rated for participants with rating lower than 2100. We will be pleased 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, one of which contains subtasks. You will have 2 hours and 15 minutes to solve them. Scoring distribution will be announced later.

We would like to thank everyone who helped with this round:

• errorgorn for coordinating the round. He really helped a lot as it's our first time setting up a round on Codeforces.
• Runtime-Terr0r, maomao90, mana, milind0110, Dominater069, Codula, Everule, fengzhengwei, feecIe6418, AlperenT, 18o3 and rsj for testing the round and providing valuable feedbacks, and for all your help in improving this round's quality.
• Alexdat2000 for Russian translation.
• Talaodi for setting no problems finally being our mascot for the round.
• MikeMirzayanov for the great Codeforces and Polygon platforms.
• You, for participating in the round.

We are looking forward to your participation. Good luck and Have fun!

UPD1: Score distribution: $$$500-1000-1750-2000-2250-(2500+1500)$$$

UPD2: Editorial

UPD3: Congratulations to the winners!

Official winners:

1. MoFalkmusic
2. Goldenglowo
3. 2021_yes
4. Terry2022
5. gajar.nouka

Unofficial winners:

1. BucketPotato
2. MoFalkmusic
3. Goldenglowo
4. tute7627
5. 2021_yes

The XI BSUIR Open Programming Championship will be held from March 15 till April 29, 2023 (Minsk, Belarus).

Undergraduates and postgraduates of BSUIR, scholars, students from other universities and countries are invited to participate in the Championship.

The competition will take place in several rounds:

• Quarterfinals (distance, problems in Russian and English) — March 15 — March 20 (both included);
• Semifinals (distance/onsite semi-final, russian and english problems) — April 6;
• Students Final — April 22 (Belarusian State University of Informatics and Radioelectronics, Minsk);
• Schools Final — April 29 (Belarusian State University of Informatics and Radioelectronics, Minsk).

Quarterfinals are required only for BSUIR and school teams but other registered teams can also take part in it. Semifinals are required for all teams. BSUIR and school teams from Belarus take part onsite, other teams — online. Semifinals and Finals will be in ICPC format (5h contest).

To participate in the Championship teams need to be registered prior to April 3, 2023. Participation is free of charge — have fun.

The finalists are 30 (or more by jury decision) students teams, showed the best results in the qualifying rounds, but no more than:

• 7 teams of undergraduates and postgraduates of BSUIR;
• 2 teams from each of the universities of Belarus and abroad.

And 25 school teams showed the best results in the qualifying rounds.

University teams, which include at least two ICPC finalists 2022-2023, as well as high school teams, which include at least two winners of the final stage of the National Belarusian Olympiad in Informatics 2023, are allowed to participate in the finals of the Championship without passing the qualifying rounds.

Open BSUIR Programming Championship is held by the ICPC rules. During the Championship, the teams will be given 5 hours to solve 8 to 12 programming problems.

More information about the championship, as well as the problems and results of previous years, you may find at acm.bsuir.by.

here's a link there to a telegram channel and discussion, where you can talk to other participants and team up.

A little bit of last year video:
https://www.youtube.com/watch?v=nFZpkUFAO6Q
https://www.youtube.com/watch?v=07E0APqaB20

Hello, Codeforces!

Zlobober and I are glad to invite you to compete in Nebius Welcome Round (Div. 1 + Div. 2) that will start on Mar/12/2023 17:35 (Moscow time). 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, aymanriadsolh, Vladik, Junco_dh, dshindov, csegura, Eddard, Alexdat2000, kLOLik, wuruzhao, Aleks5d, Ryougi-Shiki, qrort, ak2006, AsGreyWolf, farmerboy, vladukha, usernameson, ZiXeL, DzumDzum, Java, samvel, mister, 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, antony191, 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.com/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, chickensqaure, 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. ErdemKirez
5. izhang

Unofficial winners:

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