AliShahali1382's blog

By AliShahali1382, history, 10 months ago, In English

Hello, Codeforces!

On 23.11.2021 17:35 (Московское время) we will host Codeforces Global Round 17.

It is the fifth 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 AliShahali1382(Ali Shahali), AmShZ(AmirMohammad ShahRezaei), DeadlyCritic(MohammadHossein Paydar), Keshi(Alireza Keshavarz), alireza_kaviani(Alireza Kaviani).

We would like to thank these people:

You will have 3 hours to solve 9 problems. As usual, it is highly recommended to read all problems!

The score distribution will be announced at least 5 minutes before the round starts! :)

Score distribution : 500 — 1000 — 1500 — 2250 — 2500 — 2750 — 3250 — 3500 — 4000.

Editorial is out

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Announcement of Codeforces Global Round 17
 
 
 
 
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By AliShahali1382, history, 16 months ago, In English

Hi, Codeforces!

1529A - Eshag Loves Big Arrays

problem idea and solution: AmShZ

editorial
official solution

1529B - Sifid and Strange Subsequences

problem idea and solution: Davoth

editorial
official solution

1528A - Parsa's Humongous Tree

problem idea and solution: shokouf, AmShZ

editorial
official solution

1528B - Kavi on Pairing Duty

problem idea and solution: alireza_kaviani

editorial
official solution

1528C - Trees of Tranquillity

problem idea and solution: AliShahali1382

editorial
official solution
better implementation of official solution: AaParsa
python solution: Tet
another O(n.log) solution with seg-tree: N.N_2004

1528D - It's a bird! No, it's a plane! No, it's AaParsa!

problem idea and solution: AmShZ, AliShahali1382

editorial
official solution
a different O(n^3) solution: Atreus

1528E - Mashtali and Hagh Trees

problem idea and solution: AliShahali1382

Thanks to Kininarimasu for the editorial.

editorial
official solution

1528F - AmShZ Farm

problem idea and solution: AmShZ, AliShahali1382

editorial
official solution

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By AliShahali1382, history, 23 months ago, In English
$$$~-\text{In the name of God}~-$$$

Hello Codeforces,

I'm glad to invite you to our first contest Codeforces Round #684 (Div. 1) and Codeforces Round #684 (Div. 2) which will be held at 17.11.2020 17:35 (Московское время) . The problems are invented and prepared by AliShahali1382, Mehrdad_Sohrabi, and Mohammad.H915. The round is rated for both divisions. You will be given 5 problems and 2 hours 15 minutes to solve them. I recommend you to read all the problems :)

Firstly I'd like to thank isaf27 for coordinating and reviewing the round, as well as helping with many different things.

Thanks for our testers 300iq, growup974, Atreus, Shayan.P, Retired_cherry, morzer, BledDest, UnstoppableChillMachine, MAMBA, prabowo, WNG for testing and giving very helpful advice.

Finally, thanks to MikeMirzayanov for very nice and convenient Codeforces and Polygon platforms.

I hope you all will find the problems interesting. I wish you high scores and good luck!

Scoring distribution:

Div. 1: (500-500)-1250-1750-2500-2500

Div. 2: 500-1000-(750-750)-2000-2500

UPD : Editorial is out.

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