Hello, Codeforces!

After a year of anticipation and several complete changes to the problem set, we are glad to invite you to take part in Codeforces Round 948 (Div. 2), which will start on Sunday, May/26/2024 17:35 (Moscow time). This round will be rated for participants whose rating is below 2100. Participants with higher ratings may participate out of the competition.

You will be given 5 problems and 2 hours to solve them. All the problems in the round are created and prepared by Stefan2417 and alexchist.

The round may include one or more interactive problems. Please read this blog to get familiar with this type of problems.

We would like to thank:

• Vladithur for excellent round coordination!

• A_G, JustNik77, AgafonovArtem, MADKIRUS, AndreyPavlov, PBBx0, Alexdat2000, RP-1, mwen, MrDelrus, tiom4eg, ezraft, TheEvilBird, Codula, Vamperox for testing the round and providing valuable feedback.

• MikeMirzayanov, geranazavr555, geranazavr555, vbandurin, ChurakovaAlexandra, medvezhonokok, Vladosiya and KAN for maintaining and developing the Codeforces and Polygon platforms!

Score distribution: $$$500 — 1250 — 1750 — 2000 — 2500$$$.

Your perception of the scoring may vary, so be sure to read the later problems if you get stuck on one.

Upd: Congratulations to the Winners!

Div 2:

1. sun_gan_chou_yu_guan

2. Maksiwelle

3. suomynonA

4. new_mistakes

5. Kosyaaa

Div 1+2:

1. tourist

2. Sugar_fan

3. sun_gan_chou_yu_guan

4. abc864197532

5. BurnedChicken

Upd: editorial

Hello, Codeforces! Or, as we like to say in Servalish (created by Serval): High-low, Cold-for-seize!

We are glad to invite you to participate in Codeforces Round 947 (Div. 1 + Div. 2), which will start on May/25/2024 17:35 (Moscow time). The round is a combined round and will be rated for everyone.

The problems are prepared by Atomic-Jellyfish, Nerovix, SanweiTreap, Serval, Toxel, jhdonghj112 and me. You will be given 9 problems to solve in 3 hours. Scoring distribution will be announced later.

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

• errorgorn for his 🐸, 😱, 👍 and 🥶 coordination.
• Alexdat2000 for Russian translation.
• BFLSTiger and wzy2001wzy for providing some rejected problem proposals and discussing problems with us.
• 2sozx, JJLeo, YUKI_LELOUCH, Hanghang007, zlc1114, fried-chicken, zhicheng, fsfdgdg, H_W_Y, 200815147, CrTsIr, OMG_link, RDDCCD, SSerxhs, Tony2_CF, zhaohaikun, Hank2019, WZKQWQ, cxaphoenix, LGyxj, Oshwiciqwqq, fallleaves01, forget-star, monstersqaq, Narukara, Ricky2021, MagicalFlower, Saule_, kgqy, YSY_, dan_dolmatov, lowbob, sleepwa1ker, Nanako, Qingyu, Meatherm, PersistentLife2024, Vamperox, FransValli, skywalkert, shstyle, Lavine, kaichou243, gamegame, Cai_Guang, xhytom, qiuzx, Legitimity, Kevin114514, Adam_GS, htetgm, zengminghao, Melania, JCY_, yaoxi, schrodingerstom, jqdai0815, SSH_automaton, platelet and sjc061031 for testing the round and providing valuable feedbacks.
• MikeMirzayanov for the amazing Codeforces and Polygon platforms.
• You for participating in the round.

We recommend you to read the statements of all problems. Good luck & Have fun! (=・ω・=)

UPD: Scoring distribution: 250-500-1000-1500-2000-2500-3000-4500-6000

UPD2: Editorial is available now.

UPD3: Thank you for your participation in this round! Congratulations to the winners:

1. tourist
2. Golovanov399
3. maspy
4. hos.lyric
5. Um_nik

And the first solves on each problem:

• A: abdo3bkr
• B: Asaemon
• C: tourist
• D: tourist
• E: maspy
• F: tourist
• G: maspy
• H: Golovanov399
• I: Ormlis

UPD4: Chinese editorial is available now.

Photo of reviewer and some authors:

We invite you to first ICPC alumni event in Silicon Valley on June 4 at 6pm.

This is a unique event that will bring together top ICPC alumni and friends. The event will be attended by ICPC President Bill Poucher, Freedom Holding CEO Timur Turlov and Bagdat Mussin, President of the Kazakh Federation of Competitive Programming.

Register here: https://lu.ma/ICPC_Meetup

P.S: wdyt about some small entertainy contest?

Hello! Codeforces Round 946 (Div. 3) will start at May/20/2024 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 7 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.

Round is based on UKIEPC 2024: Spring Practice. Please refrain from participating in this round if you are familiar with the tasks of this competition.

I would like to thank:

1. Authors of the original competition: Aksenov239, MaxBuzz, RobinFromTheHood, darnley, izban, pkhaustov, lsantire, az453, fedor.tsarev, Shoaib Jameel.

2. MikeMirzayanov for help with ideas and Polygon and Codeforces platforms.

3. -is-this-fft-, peltorator, tute7627 for red testing.

4. senjougaharin, kaikey, gmusya, nskybytskyi, Giga_Cronos, diskoteka for yellow testing.

5. TypeYippie, kzyKT, tepamid, ahshafi for purple testing.

6. Abo_Samrah, Zandler, sam07a, YESMAKHAN, xygzy, Klaus26 for blue testing.

7. Morvolzz, dasha..zhilina, sutekine, Muhsen, Gojova, Acanikolic73 for cyan testing.

8. You for participation.

Good luck!

UPD: Editorial is out.

Ahoj, Codeforces!

We are excited to invite you to participate in Codeforces Round 945 (Div. 2), which will start on May/17/2024 17:35 (Moscow time).

The problems are authored by TimDee and prvocislo.

This round will be rated for participants whose rating is below $$$2100$$$. Participants with higher ratings are encouraged to participate out of the competition.

You will be given $$$6$$$ problems and $$$2$$$ hours to solve them. The scoring distribution is bellow. One of the problems will be interactive. Please read this blog to get familiar with this type of problems.

We would like to thank everyone, who made this round happen:

• You for participating in this round! I hope you will enjoy the problems!

• satyam343 for great coordination and discussion of the problem ideas!

• KAN for providing suggestions to help us make the round better

• MikeMirzayanov for the amazing Codeforces and Polygon platforms!

• Alexdat2000 for Russian translations

• Our loyal army of testers: A_G, Adam_GS, errorgorn, Dominater069, valeriu, atodo, Ritwin, MridulAhi, NemanjaSo2005, Sanat, tyr0Whiz yuvrajKharayat, 18o3, Phantom_Performer, mesanu, tushaar9876, madlogic, callmepandey, Scythe, htetgm, Blagoj, Non-origination, Abhishek_Srivastava and ✩₊ myvaluska ₊✧ , for pointing out mistakes and helping us improve the round!

• Last but not least, I, prvocislo, would like to thank atodo and misof for inspiring me to start with problem-setting.

Scoring distribution: $$$500-1000-1500-2000-2250-3000$$$

Good luck, have fun and see you on Friday! ✩₊˚

Upd: Congratulations to the Winners!

Div 2:

1) _MyGO_Tomori_

2) Sxy_Limit

3) LofiGirl

4) prins

5) SXWZ-Queenie

Div 1+2:

1) BucketPotato with first AK!

2) gamegame

3) hitonanode

4) abc864197532

5) peti1234

Upd2: Editorial is out!

Hi everyone!

We organized an onsite competitive programming contest at ETH Zürich on May 11th, 2024. The contest is now uploaded to the Codeforces gym at ETH Zurich Competitive Programming Contest Spring 2024.

The onsite contest was 5h long and we recommend for you to participate in teams. In the onsite contest only one computer was allowed but participants could access the internet freely. The difficulty of the problemset is slightly easier than a regional ICPC contest but also offers a few hard problems. Difficulty range is from div2 A to div2 G.

Thanks a lot to all problem setters: BenniKartefla, Lakii, Lebossle, MihneaDAVID, OhLee, TecTrixer, ackj, adamant, alagorithmet and mango_lassi.

Additionally, a big thanks to all our testers and reviewers: Petr, Evirir, CSQ31, atakanysr, FatihSolak, qwexd, AhmetKaan, Macdu, atli164, SATSKY_2024target_IGM, SuprDewd, Tagl, Tobo, wildfire032, fried-chicken, theodor.moroianu and sischu74.

Tutorial Slides can be found here.

Congratulations to the top 5 of the onsite contest:

1. mETHroners: GRT_2018, Meloric, paula
2. Mr Malnars Lethal Peppers: pavkal5, DBradac, dpaleka
3. uhh this should actually be first place, sorry, system error: AimShootReload, donentseto
4. ML and AC: miguell, Andrei1998
5. CrispyBeef: tiagodias, jonathanplsmith, Blackphoenyx

Greetings Codeforces!

First things first, we would like to thank everyone who participated in the previous nine Kotlin Heroes competitions: Episode 1, Episode 2, Episode 3, Episode 4, Episode 5: ICPC Round, Episode 6, Episode 7, Episode 8 and Episode 9.

Kotlin Heroes is a great way to play around with Kotlin’s features, learn something new, and practice using the language by solving fun problems. It is great for programmers of any level!

We invite you to join the practice round, where you can improve your algorithmic problem-solving skills and complete training problems. In this round, all the solutions are open and you can request hints if you’re stuck.

Here are some things you can do to help you refresh your knowledge of Kotlin and learn more about competitive programming while you practice:

• Review our Kotlin solutions for the Advent of Code algorithmic puzzles.
• Read our competitive programming tutorial.
• Watch the videos from our Kotlin in Competitive Programming YouTube playlist.
• Look at the problems from the previous practice rounds.

On May 13, 2024, the real challenge begins! Kotlin Heroes: Episode 10 will last 2 hours 30 minutes and will feature a set of problems ranging from simple ones, which are designed to be solvable by anyone, to some really tricky ones for seasoned competitive programmers.

You can solve Codeforces challenges directly from your JetBrains IDE using its smart features. Just enable the JetBrains Academy plugin and follow the instructions in the Getting started with Codeforces guide.

Prizes:

The top three winners will receive cash prizes of $512, $256, and $128 (or rewards of equivalent value), respectively. The top 50 participants will win a Kotlin Heroes T-shirt and an exclusive Kotlin sticker, and all competitors who solve at least one problem will be entered into a raffle for one of 50 Kotlin Heroes T-shirts.

Please note that we are not able to ship prizes to any country, state, province, or territory subject to comprehensive OFAC sanctions, including Belarus, Cuba, Iran, North Korea, Russia, Syria, or the Crimea, Donetsk, or Luhansk regions. To see the list of sanctioned countries and regions, please visit this page.

Best of luck to everyone!