Vladosiya's blog

By Vladosiya, history, 5 weeks ago, In English

2000A - Primary Task

Idea: senjougaharin

Tutorial
Solution

2000B - Seating in a Bus

Idea: myav

Tutorial
Solution

2000C - Numeric String Template

Idea: myav

Tutorial
Solution

2000D - Right Left Wrong

Idea: Vladosiya

Tutorial
Solution

2000E - Photoshoot for Gorillas

Idea: Vladosiya

Tutorial
Solution

2000F - Color Rows and Columns

Idea: senjougaharin

Tutorial
Solution

2000G - Call During the Journey

Idea: senjougaharin

Tutorial
Solution

2000H - Ksyusha and the Loaded Set

Idea: senjougaharin

Tutorial
Solution

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By Vladosiya, history, 5 weeks ago, translation, In English

Hello! Codeforces Round 966 (Div. 3) will start at Aug/13/2024 17:40 (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. After open hacks all accepted solutions will be rejudged on successful 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.

Problems have been created and written by our team: myav, Gornak40, senjougaharin and Vladosiya.

We would like to thank:

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

  2. FairyWinx, TheScrasse, Be_dos for red testing.

  3. irkstepanov, Kirkon, ikrpprppp, Kaey, Bruteforceman for yellow testing.

  4. Vitaly503, FBI for purple testing.

  5. satyam343, vikram108 for blue testing.

  6. trgt26 for green testing.

Good luck!

UPD: Editorial is out.

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By Vladosiya, history, 4 months ago, In English

1980A - Problem Generator

Idea: Vladosiya Prepared by: Vladosiya

Tutorial
Solution

1980B - Choosing Cubes

Idea: senjougaharin Prepared by: senjougaharin

Tutorial
Solution

1980C - Sofia and the Lost Operations

Idea: senjougaharin Prepared by: Gornak40

Tutorial
Solution

1980D - GCD-sequence

Idea: myav Prepared by: myav

Tutorial
Solution

1980E - Permutation of Rows and Columns

Idea: senjougaharin Prepared by: senjougaharin

Tutorial
Solution

1980F1 - Field Division (easy version)

Idea: MikeMirzayanov Prepared by: Vladosiya

Tutorial
Solution

1980F2 - Field Division (hard version)

Idea: MikeMirzayanov Prepared by: Vladosiya

Tutorial
Solution

1980G - Yasya and the Mysterious Tree

Idea: Gornak40 Prepared by: Gornak40

Tutorial
Solution

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By Vladosiya, history, 4 months ago, translation, In English

Hello! Codeforces Round 950 (Div. 3) will start at Jun/03/2024 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. After open hacks all accepted solutions will be rejudged on successful 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.

Problems have been created and written by our team: myav, Gornak40, senjougaharin and Vladosiya.

We would like to thank:

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

  2. Be_dos, Dominater069, 74TrAkToR, BucketPotato for red testing.

  3. KseniaShk, cry, tolbi, ScarletS, nskybytskyi, sevlll777 for yellow testing.

  4. mahdi.hasnat, Phantom_Performer, mainyutin for purple testing.

  5. natalina, FBI, Kopite, MADE_IN_HEAVEN, mz1 for blue testing.

  6. Romakolesn for cyan testing.

Good luck!

P.S.: We are aware of the error that occurred while updating the ratings for Educational Codeforces Round 166. It will be fixed before this round. UPD: We fixed it!

UPD: Editorial is out!

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By Vladosiya, history, 4 months ago, In English

1974A - Phone Desktop

Idea: Aksenov239

Tutorial
Solution

1974B - Symmetric Encoding

Idea: MikeMirzayanov

Tutorial
Solution

1974C - Beautiful Triple Pairs

Idea: MikeMirzayanov

Tutorial
Solution

1974D - Ingenuity-2

Idea: MaxBuzz

Tutorial
Solution

1974E - Money Buys Happiness

Idea: RobinFromTheHood

Tutorial
Solution

1974F - Cutting Game

Idea: MikeMirzayanov

Tutorial
Solution

1974G - Money Buys Less Happiness Now

Idea: RobinFromTheHood, izban, Aksenov239

Tutorial
Solution

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By Vladosiya, history, 4 months ago, translation, In English

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.

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By Vladosiya, history, 7 months ago, translation, In English

1932A - Thorns and Coins

Idea: denk

Tutorial
Solution

1932B - Chaya Calendar

Idea: Vladosiya

Tutorial
Solution

1932C - LR-remainders

Idea: MikeMirzayanov

Tutorial
Solution

1932D - Card Game

Idea: goncharovmike

Tutorial
Solution

1932E - Final Countdown

Idea: step_by_step

Tutorial
Solution

1932F - Feed Cats

Idea: denk

Tutorial
Solution

1932G - Moving Platforms

Idea: denk

Tutorial
Solution

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By Vladosiya, history, 7 months ago, translation, In English

1931A - Recovering a Small String

Idea: myav Prepared by: myav

Tutorial
Solution

1931B - Make Equal

Idea: MikeMirzayanov Prepared by: Vladosiya

Tutorial
Solution

1931C - Make Equal Again

Idea: senjougaharin Prepared by: senjougaharin

Tutorial
Solution

1931D - Divisible Pairs

Idea: MikeMirzayanov Prepared by: Vladosiya

Tutorial
Solution

1931E - Anna and the Valentine's Day Gift

Idea: Gornak40 Prepared by: Gornak40

Tutorial
Solution

1931F - Chat Screenshots

Idea: senjougaharin Prepared by: senjougaharin

Tutorial
Solution

1931G - One-Dimensional Puzzle

Idea: senjougaharin Prepared by: senjougaharin

Tutorial
Solution

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By Vladosiya, history, 7 months ago, translation, In English

Hello! Codeforces Round 925 (Div. 3) will start at Feb/13/2024 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.

Problems have been created and written by our team: myav, Gornak40, senjougaharin and Vladosiya.

We would like to thank:

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

  2. nigus for red testing.

  3. vladmart, Gheal, KseniaShk for yellow testing.

  4. htetgm for purple testing.

  5. natalina, SashaT9, lockdown, bma20006 for blue testing.

  6. RedDreams for cyan testing.

  7. the_Incharge, Aurora__, Longqiang for green testing

Good luck!

P.S. Happy Valentine's Day!

UPD: Let's continue streak of announces with photo of the authors :)

UPD2: Editorial

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By Vladosiya, history, 7 months ago, In English

1927A - Make it White

Idea: MikeMirzayanov

Tutorial
Solution

1927B - Following the String

Idea: MikeMirzayanov

Tutorial
Solution

1927C - Choose the Different Ones!

Idea: MikeMirzayanov

Tutorial
Solution

1927D - Find the Different Ones!

Idea: MikeMirzayanov

Tutorial
Solution

1927E - Klever Permutation

Idea: MikeMirzayanov

Tutorial
Solution

1927F - Microcycle

Idea: MikeMirzayanov

Tutorial
Solution

1927G - Paint Charges

Idea: MikeMirzayanov

Tutorial
Solution

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By Vladosiya, history, 10 months ago, translation, In English

1907A - Rook

Idea: pashka

Tutorial
Solution

1907B - YetnotherrokenKeoard

Idea: pashka, MikeMirzayanov

Tutorial
Solution

1907C - Removal of Unattractive Pairs

Idea: Vladosiya

Tutorial
Solution

1907D - Jumping Through Segments

Idea: MikeMirzayanov, Vladosiya

Tutorial
Solution

1907E - Good Triples

Idea: pashka

Tutorial
Solution

1907F - Shift and Reverse

Idea: pashka

Tutorial
Solution

1907G - Lights

Idea: pashka

Tutorial
Solution

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By Vladosiya, history, 10 months ago, translation, In English

Hello! Codeforces Round 913 (Div. 3) will start at Dec/05/2023 17:45 (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.

Problems have been created and written by pashka, MikeMirzayanov and me.

Part of the problems in this round were in the Cyprus Programming Challenge. If you participated in it, please refrain from participating in this round.

We would like to thank:

  1. peltorator, FairyWinx for red testing.
  2. Vladithur, Valters07 for yellow testing.
  3. stefanbalaz2, FBI, SlavicG, flamestorm, SashaT9, mesanu, trainerherp, Ush1su for purple testing.
  4. dan_dolmatov, Yousef.Osama for blue testing.
  5. Sergey140146659, Pa_sha, gas for cyan testing.

Good luck!

UPD: Editorial

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By Vladosiya, history, 10 months ago, translation, In English

Hello, Codeforces!

I wanted to add CERC 2021 to gyms, but I can't seem to find the tests, checkers, and solutions. If you know where they can be found or someone who might have them, please let me know.

UPD: Thanks everyone for help and xiaowuc1 who shared the archive to me!

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By Vladosiya, history, 11 months ago, translation, In English

1881A - Don't Try to Count

Idea: Vladosiya

Tutorial
Solution

1881B - Three Threadlets

Idea: Gornak40

Tutorial
Solution

1881C - Perfect Square

Idea: myav, MikeMirzayanov, Vladosiya

Tutorial
Solution

1881D - Divide and Equalize

Idea: myav

Tutorial
Solution

1881E - Block Sequence

Idea: MikeMirzayanov

Tutorial
Solution

1881F - Minimum Maximum Distance

Idea: senjougaharin

Tutorial
Solution

1881G - Anya and the Mysterious String

Idea: Gornak40

Tutorial
Solution

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By Vladosiya, history, 11 months ago, translation, In English

Hello! Codeforces Round 903 (Div. 3) will start at Oct/12/2023 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 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.

Problems have been created and written by our team: myav, Gornak40, senjougaharin and Vladosiya.

We would like to thank:

  1. MikeMirzayanov for Polygon and Codeforces platforms.

  2. SomethingNew, rniya, zwezdinv for red testing.

  3. makrav, snowysecret, AlexanderL, KseniaShk, pavlekn for yellow testing.

  4. gigabuffoon, EgorUlin, KerakTelor, Pa_sha, I_love_geom, petyb, MinaRagy06, toniskrijelj, FynjyBath for purple testing.

  5. Abo_Samrah, dan_dolmatov, pedrosorio, ezdp, azureglow, Chrisedyong, Apachee, arseny2606 for blue testing.

  6. t0rtik, Sergey140146659, hader239, Modern for cyan testing.

  7. mkshh, petertromso for green testing.

Good luck!

UPD: Editorial

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By Vladosiya, history, 12 months ago, In English

Hello, Codeforces!

We've compiled a list of command lines that Codeforces uses to compile and run solutions in various languages and compilers.

It is up-to-date as of today (2023-10-06), and we will make efforts to keep it current in the future, but this is not guaranteed.

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By Vladosiya, history, 12 months ago, translation, In English

Hello, Codeforces! A month ago, I started working part-time with MikeMirzayanov. It's time to share the results of the first month!

Overall, I've been involved in several things:

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By Vladosiya, history, 13 months ago, In English

Hello, Codeforces!

Today, MikeMirzayanov taught me how to add contests to the Gym, so we've started adding old Google Code Jam rounds. We think it's a good idea to create a comprehensive (or almost comprehensive) archive of all GCJ rounds in the Gym.

I've added 2015 Google Code Jam Round 1A (GCJ 15 Round 1A) and 2015 Google Code Jam Round 1C (GCJ 15 Round 1C) today. It seems that for the 2015 season, only the Finals are missing now. I'll be adding that soon as well!

While Google's archives don't include solutions, we did find a user-generated archive at https://github.com/kamyu104/GoogleCodeJam-2015. However, it would be great to have additional sources for verification.

Would any of you be able to help us find other reliable sources for correct solutions? This way, we can be absolutely sure that all uploaded problems are accurate.

Thank you!

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Tags gcj
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By Vladosiya, history, 14 months ago, translation, In English

Hello, Codeforces! I made announces of rounds quite often, so some time ago I made a script that gives out the entire list of testers divided by colors. Of course, you can rewrite it a little, so that the order is whatever you want.

Script uses Codeforces API, so first of all you need to go to your account settings and generate API keys and put the open one in the "key" file, and the secret one in the "secret" file in the same folder with the script (or just assign them to the corresponding variables in the script). Now you just need to fill in the array contestids with ids of mashups that you used for testing and run the script. At the end of its work, the script will create file "en.txt " with thanks to all the testers.

I hope it will help you to quickly change the list of testers. Good luck to all and successful rounds!

Script

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By Vladosiya, history, 14 months ago, In English

1851A - Escalator Conversations

Idea: Vladosiya, prepared: Aris

Tutorial
Solution

1851B - Parity Sort

Idea: Vladosiya, prepared: myav

Tutorial
Solution

1851C - Tiles Comeback

Idea: Vladosiya, prepared: myav

Tutorial
Solution

1851D - Prefix Permutation Sums

Idea: Gornak40, prepared: senjougaharin

Tutorial
Solution

1851E - Nastya and Potions

Idea: Vladosiya, prepared: Vladosiya

Tutorial
Solution

1851F - Lisa and the Martians

Idea: Gornak40, prepared: Gornak40

Tutorial
Solution

1851G - Vlad and the Mountains

Idea: Vladosiya, prepared: Vladosiya

Tutorial
Solution

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By Vladosiya, history, 14 months ago, translation, In English

Hello! Codeforces Round 888 (Div. 3) will start at Jul/25/2023 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 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.

Problems have been created and written by our team: myav, Aris, Gornak40, senjougaharin and Vladosiya.

We would like to thank:

  1. MikeMirzayanov for Polygon and Codeforces platforms.

  2. tute7627 for red testing

  3. oversolver, sevlll777, pavlekn, zwezdinv, Sokol080808, 74TrAkToR, vladmart, EJIC_B_KEDAX, Vladithur, KseniaShk, Be_dos for yellow testing

  4. moonpie24, FBI, meowcneil, NintsiChkhaidze, Phantom_Performer, SashaT9, spike1236, Kalashnikov for purple testing

  5. TheGoodest, Pa_sha, Sasha0738 for blue testing

  6. Syuzi777, Tahseen for cyan testing

Good luck!

UPD: Editorial

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By Vladosiya, history, 16 months ago, In English

1833A - Musical Puzzle

Idea: Vladosiya, prepared: Vladosiya

Tutorial
Solution

1833B - Restore the Weather

Idea: myav, prepared: myav

Tutorial
Solution

1833C - Vlad Building Beautiful Array

Idea: Vladosiya, prepared: Vladosiya

Tutorial
Solution

1833D - Flipper

Idea: Gornak40, prepared: Aris

Tutorial
Solution

1833E - Round Dance

Idea: MikeMirzayanov, Vladosiya, prepared: senjougaharin

Tutorial
Solution

1833F - Ira and Flamenco

Idea: Gornak40, prepared: Gornak40

Tutorial
Solution

1833G - Ksyusha and Chinchilla

Idea: Gornak40, prepared: Gornak40

Tutorial
Solution

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By Vladosiya, history, 16 months ago, translation, In English

Hello! Codeforces Round 874 (Div. 3) will start at May/19/2023 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: pavlekn, KoT_OsKaR, natalina, vladmart, Phantom_Performer, Be_dos, ctraxxd, diskoteka, lunchbox, kzyKT, MODDI, molney, FEDIKUS, Nickir, 74TrAkToR, kamishogun, KseniaShk, Sokol080808, NintsiChkhaidze, Asad5059, heon for testing the contest and valuable feedback. List of testers will be updated.

Good luck!

UPD: Editorial

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By Vladosiya, 18 months ago, translation, In English

1811A - Insert Digit

Idea: senjougaharin, prepared: senjougaharin

Tutorial
Solution

1811B - Conveyor Belts

Idea: Vladosiya, prepared: senjougaharin

Tutorial
Solution

1811C - Restore the Array

Idea: MikeMirzayanov, prepared: myav

Tutorial
Solution

1811D - Umka and a Long Flight

Idea: Gornak40, prepared: Gornak40

Tutorial
Solution

1811E - Living Sequence

Idea: Aris, prepared: Aris

Tutorial
Solution

1811F - Is It Flower?

Idea: Vladosiya, prepared: Vladosiya

Tutorial
Solution

1811G1 - Vlad and the Nice Paths (easy version)

Idea: Vladosiya, prepared: Vladosiya

Tutorial
Solution

1811G2 - Vlad and the Nice Paths (hard version)

Idea: Vladosiya, prepared: Vladosiya

Tutorial
Solution

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By Vladosiya, 18 months ago, translation, In English

Hello! Codeforces Round 863 (Div. 3) will start at Apr/04/2023 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: Sugar_fan, doreshnikov, powergee101, pashka, KseniaShk, 74TrAkToR, stefanbalaz2, playerr17, diskoteka, BF_OF_Priety, nigus, erankyun, plourde27, Be_dos, donghoony, lucasxia01, Jostic11, sansen, gigabuffoon, akulenok, pwned, vrintle for testing the contest and valuable feedback. List of testers will be updated.

Good luck!

UPD: Editorial

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