DishonoredRighteous's blog

By DishonoredRighteous, history, 19 months ago, In English

1820A - Yura's New Name

Author: FairyWinx

Preparation: FairyWinx

Editorial
Solution

1820B - JoJo's Incredible Adventures

Author: golikovnik

Preparation: teraqqq

Editorial
Solution

1819A - Constructive Problem

Author: TeaTime

Preparation: golikovnik

Editorial
Solution

1819B - The Butcher

Author: Tikhon228

Preparation: Kon567889

Editorial
Solution

1819C - The Fox and the Complete Tree Traversal

Author: golikovnik

Preparation: DishonoredRighteous

Editorial
Solution

1819D - Misha and Apples

Author: Um_nik

Preparation: dshindov

Editorial
Solution

1819E - Roads in E City

Author: Tikhon228

Preparation: grphil

Editorial
Solution

1819F - Willy-nilly, Crack, Into Release!

Author: teraqqq

Preparation: teraqqq

Editorial
Solution

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By DishonoredRighteous, history, 19 months ago, In English

Hello, Codeforces!

This Saturday VIII Lipetsk Team Olympiad, a competition for high school students from all over the country, will be held in Lipetsk. Maybe you participated in previous Codeforces rounds based on our problems (rounds 643 and 791).

The round will start at 15.04.2023 12:05 (Московское время) and will last for 2 hours. Please notice the unusual time. Each division will have 6 problems. The round will be held according to the Codeforces rules and will be rated for both divisions.

Problems were proposed and prepared by Um_nik, DishonoredRighteous, FairyWinx, golikovnik, teraqqq, grphil, Kon567889, TeaTime, Tikhon228 and dshindov.

I would like to thank Artyom123 for great round coordination and our testers: Ormlis, bashkort, Umi, I_LOVE_ANTON_DONBASS, Egor.Lifar, iakovlev.zakhar, Mangooste, Siberian, SomethingNew, stepanov.aa, talant, rt3, towrist, Aaeria, Alexdat2000, qxforever, Renatyss, Renedyn, sevlll777, towrist, valerikk, Tiagodfs, wiz_cs, Setsuna, ezraft, Gornak40, HunterXD, kbats183, Nathan_McKane, nik_sn, Nitelike, Tilt, ak2006, KiruxaLight, 9kin.

Of course, I would like to thank all Codeforces team for this beautiful platform!

Scoring distribution will be announced later.

I hope you will enjoy our problems. Wish you good luck and high rating!

UPD: Scoring distribution:

Div.1: 750 – 1250 – 1500 – 2000 – 2750 – 3000

Div.2: 500 – 1000 – 1750 – 2000 – 2500 – 3500

UPD: Winners!

Div 2:

Div 1:

UPD: Editorial is available here

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By DishonoredRighteous, history, 2 years ago, In English

1679A - AvtoBus

Author: iakovlev.zakhar

Preparation: DishonoredRighteous

Editorial: DishonoredRighteous

Editorial

1679B - Stone Age Problem

Author: Kon567889

Preparation: Kon567889

Editorial: DishonoredRighteous and Kon567889

Editorial

1679C - Rooks Defenders

Author: Kon567889

Preparation: Kon567889

Editorial: DishonoredRighteous and Kon567889

Editorial

1679D - Toss a Coin to Your Graph...

Author: Kon567889

Preparation: Masha237

Editorial: DishonoredRighteous

Editorial

1679E - Typical Party in Dorm

Author: andr1y and welleyth

Preparation: andr1y and welleyth

Editorial: andr1y and welleyth

Editorial

1679F - Formalism for Formalism

Author: iura

Preparation: iura

Editorial: DishonoredRighteous

Editorial

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By DishonoredRighteous, 2 years ago, In English

Hello, Codeforces!

I'm glad to invite you to Round 791 which will start at 14.05.2022 12:35 (Московское время). Please notice the unusual time.

There will be 6 problems in the round. Round is based on Team Olympiad in Lipetsk which is being held for the seventh time. Problems were proposed and prepared by iakovlev.zakhar, Kon567889, iura, andr1y, Masha237, welleyth and me. I would like to thank Aleks5d and KAN for CF round coordination and testers: Um_nik, 353cerega, errorgorn, Stepavly, divanik, nnv-nick, 4qqqq, to be continued...

Of course, I'd like to thank all Codeforces team for Codeforces and Polygon beautiful platforms!

I also would like to thank golikovnik, egneeS, dshindov and Inessa Shuykova (Lipetsk teams' coach) for preparing other Olympiad problems that haven't been taken for this round.

Thanks to NEAR for supporting this round, details can be found in this post.

Note that if you are an official participant of the Olympiad, you are not allowed to participate in this round.

Scoring distribution will be announced later.

Wish you good luck and high rating!

UPD.1 Scoring distribution: $$$500 - 1000 - 1500 - 1750 - 2250 - 3000$$$.

UPD.2 Congratulations to winners!

Official participants:

  1. xiaoziyaooo

  2. StickyFingers

  3. mybing

  4. huangweiliang

  5. NewPC2022

Unofficial participants:

  1. SSRS_

  2. leaf1415

  3. uwi

  4. maspy

  5. TripleM5da

UPD.3 Editorial is available here.

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By DishonoredRighteous, history, 3 years ago, translation, In English

Hello, CodeForces!

Recently I was working on a Java library that implements interaction with Polygon API. It is very useful for some my tasks and it's cool that Polygon provides an API. But I discovered that is's kinda outdated. There are some new features in Polygon for which theres is no access through the API. There are also some use cases that can't be counted as new features but it's impossible to to them using API too.

In this post I created a shortlist of some methods and enhancements that can be useful in Polygon API in my opinion. May be it's hard to implement some of them but I hope that someone from Codeforces and Polygon team will see it and may be implement some of this API methods.

  1. Statement object doesn't store any field for interaction protocol in interactive problems. It's strange because some API methods can be used to work with interactive problems (for example, problem.interactor) but we cannot get interaction protocol from problem statements.

  2. Linux and Windows packages downloading. There is an API method problem.package that allows to download a Standard zip package. In some cases it seems to be useful to download Linux or Windows package because they include generated tests.

  3. Test object contains test input data but doesn't contain test output data. It seems that it should be easy to add this field and it can be useful too (you won't have to run generator script locally to get test output data).

  4. There is no methods that allow to work with Contest Groups. I suppose that Contest Group is a relatively new feature and that's why there is no methods for it.

  5. We cannot commit problem changes using API (may be it's done in this way for some security reasons).

  6. We cannot build packages using API.

  7. We cannot manage access to problems, contests and contest groups via API (may be it's done in this way for some security reasons).

  8. We cannot create problems and contests, and add problems to contests using API.

  9. To be continued...

May be this list is incomplete, so I will be glad if someone add some points into it in the comments. I hope that someone from Codeforces team (MikeMirzayanov? geranazavr555?) will see this post and comment it.

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By DishonoredRighteous, history, 4 years ago, In English
Tutorial is loading...

Author's solution: 80407149

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Author's solution: 80407200

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Author's solution using formulas: 80407222

Author's solution using prefix sums: 80407239

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Author's solution: 80407273

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Author's solution: 80407303

Author's solution using ternary search: 80407326

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Author's solution: 80407360

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By DishonoredRighteous, history, 4 years ago, In English

Hello, Codeforces!

I'm glad to invite you to Round 643 which will start at May/16/2020 14:35 (Moscow time). Please notice the unusual time.

There will be 6 problems in round, one of them will be interactive. If you are not familiar with interactive problems, you can learn about them here.

Round is based on Team Olympiad in Lipetsk which is being held for the fifth time. Problems were prepared by fake123, iura, Masha237, Villen3tenmerth, Inessa Shujkova (Lipetsk teams' coach) and me. I would like to thank antontrygubO_o for CF round coordination and testers: KAN, I_love_Tanya_Romanova, vepifanov, Merkurev, golikovnik, Ekler and some other people who asked me not to write about them :)

Of course, I'd like to thank all Codeforces team for this beautiful platform!

Scoring distribution will be announced later.

Wish you good luck and high rating!

UPD.1 Scoring distribution: $$$750-750-1250-1500-2000-3000$$$.

UPD.2 Editorial is available here.

UPD.3 Congratulations to winners!

Official participants:

  1. NaimSS

  2. tianxiawoyou

  3. Lomk

  4. wisteria0410ss

  5. TheOneYouWant

Unofficial participants:

  1. risujiroh

  2. jiangly

  3. 244mhq

  4. hitonanode

  5. turmax

UPD.4 Full problemset from the olympiad is available on gym: The fifth Lipetsk collegiate programming contest. Finals. 8-11 form

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