shishin's blog

By shishin, 7 days ago, In English

Hello, Codeforces!

On Sep/12/2021 17:35 (Moscow time) we will host Codeforces Global Round 16.

It is the fourth round of a 2021 series of Codeforces Global Rounds. The rounds are open and rated for everybody.

The prizes for this round:

  • 30 best participants get a t-shirt.
  • 20 t-shirts are randomly distributed among those with ranks between 31 and 500, inclusive.

The prizes for the 6-round series in 2021:

  • In each round top-100 participants get points according to the table.
  • The final result for each participant is equal to the sum of points he gets in the four rounds he placed the highest.
  • The best 20 participants over all series get sweatshirts and place certificates.

Thanks to XTX, which in 2021 supported the global rounds initiative!

The problems were written and prepared by shishin and Artyom123.

We would like to thank these people:

You will have 2.5 hours to solve 8 problems. As always, we highly recommend reading all problems. Moreover, we really hope you upsolve the problems after the round, there are some interesting things to find out!

One of these problems is interactive, please see the guide of interactive problems if you are not familiar with it.

Score Distribution:

5007501000(750 + 1000)2000250030003750

Editorial:

The editorial

Winners

System testing finished, congrats to the winners!

  1. Radewoosh
  2. tourist
  3. QAQAutoMaton
  4. jiangly
  5. ksun48
  6. Alice_foo_foo
  7. He_Ren
  8. Benq
  9. tatyam
  10. hitonanode

Read more »

Announcement of Codeforces Global Round 16
 
 
 
 
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By shishin, 7 days ago, In English

Приветики! ヾ(≧▽≦*)o

This is a meme announcement, but it will be updated too.

We are incredibly happy to invite you to a special (for us and, we hope, for you) event, Codeforces Global Round 16. It will be held on Sep/12/2021 17:35 (Moscow time), rated for everyone of course! Feel free to participate!


The problems were written and prepared by shishin and Artyom123.

We chose the green color because it matches the "Upvote" button (cyan is fine too).

You know what to do.


Huge Thanks and much Love

to great people who contributed in the round creation

These people really deserve all the warm words and that green upvotes:

  • isaf27, the one who did a lot of things for the round to happen, I just can't find the exact words to thank him orz

  • 1-gon again for being (you already know his privileges, don't you?) VIP celebrity superstar luminary notable tester
  • physics0523 for making researches about the tasks (as he always does <3)
  • 221 for his code for the editorial(*^-^*)
  • kpw29 for making the testers list a bit more colorful and for being a part of another among us meme
  • Supercell, because sometimes we play brawl stars and it helps us invent new problems
  • Microsoft for the kaomoji's used in this blog
  • MikeMirzayanov for... agh, the copy-pasted part has already ended... for his immeasurable contribution to the development of the community!

About the problems and the contest overall:

This is our third round and we tried our best to make it special for the whole Codeforces community!

You will have 2.5 hours to solve 8 problems. As always, we highly recommend reading all problems. Moreover, we really hope you upsolve the problems after the round, there are some interesting things to find out!

A formal thing we should say (◔_◔)

One of these problems is interactive, please see the guide of interactive problems if you are not familiar with it.


Score Distribution:

5007501000(750 + 1000)2000250030003750


Editorial: Editorial


Winners

System testing finished, congrats to the winners!

  1. Radewoosh
  2. tourist
  3. QAQAutoMaton
  4. jiangly
  5. ksun48
  6. Alice_foo_foo
  7. He_Ren
  8. Benq
  9. tatyam
  10. hitonanode

Read more »

 
 
 
 
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By shishin, history, 6 months ago, translation, In English

Hello again, Codeforces!

Artyom123 and I are happy to invite you to Codeforces Round #708 (Div. 2), which will take place on Mar/17/2021 17:35 (Moscow time). This round will be rated for the participants with rating lower than 2100

These are some awesome people that we would like to thank:

You will have 2 hours to solve 5 problems (and 2 subtasks). This time the statements are not related to Valorant, but we still play it sometimes.

We hope that you will like all problems and you won't face any troubles during the contest. Good luck!

The scoring distribution: 500750(750 + 500)1750(1500 + 1500)

UPD: Editorial

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By shishin, history, 6 months ago, translation, In English

We are really sorry to make the round unrated. Anyway, we hope that you enjoyed the problems!

1497A - Meximization

Idea: shishin

Tutorial
Implementation

1497B - M-arrays

Idea: Artyom123

Tutorial
Implementation

1497C1 - k-LCM (easy version)

Idea: shishin

Tutorial
Implementation

1497C2 - k-LCM (hard version)

Idea: isaf27

Tutorial
Implementation

1497D - Genius

Idea: shishin

Tutorial
Implementation

1497E1 - Square-free division (easy version)

Idea: Artyom123

Tutorial
Implementation

1497E2 - Square-free division (hard version)

Idea: isaf27

Tutorial
Implementation

Read more »

 
 
 
 
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By shishin, history, 12 months ago, In English

All problems were prepared on Polygon by me, so if you faced any problems (we know about A) I am really sorry about it.

Tutorial is loading...

Idea: shishin

Jury solution: pastebin

Tutorial is loading...

Idea: Artyom123

Jury solution: pastebin

Tutorial is loading...

Idea: shishin

Jury solution: pastebin

Tutorial is loading...

Idea: Artyom123

Jury solution: pastebin

Tutorial is loading...

Idea: shishin

Jury solution: pastebin

Tutorial is loading...

Idea: isaf27 + Kotehok3

Jury solution: pastebin

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

Hello, Codeforces!

Artyom123, Kotehok3 and I are happy to invite you to Codeforces Round #671 (Div. 2), which will be held on Sep/19/2020 17:35 (Moscow time). This round will be rated for all participants, whose rating is lower than 2100 (We really hope so).

We would like to thank:

You will be given 6 problems and 2 hours to solve them (or to play Valorant, because the contest is related to it for some reason). One problem has an easy version and a hard version.

You will have to help the agents from the game to grind that rating. Try your best as if you are playing ranked and they are your teammates!

gl hf

Here is the score distribution:

5007501250(750 + 1000)22503000

UPD: Editorial

Read more »

 
 
 
 
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