### ZhouShang2003's blog

By ZhouShang2003, 7 days ago,

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## 1991I — Grid Game

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• +164

By ZhouShang2003, 13 days ago,

Hello, Codeforces!

We are pleased to invite you to Pinely Round 4 (Div. 1 + Div. 2), which will start on Jul/28/2024 17:35 (Moscow time). The round will be rated for everyone.

You will be given 9 problems and 3 hours to solve them. There is at least one interactive problem, so please read the guide for interactive problems if you are unfamiliar with it.

The problems were authored and prepared by me.

We would like to thank:

We hope you will enjoy the round!

Score distribution: $250 - 500 - 1000 - 1500 - 2000 - 2500 - 3000 - 3500 - 4000$

The editorial is here.

Congratulations to the winners!

#### This round is made possible with the support of Pinely!

Pinely is a dynamic algorithmic trading firm with a presence in Singapore, the Netherlands, and Cyprus. We specialize in high-frequency and ultra-low latency trading. Our team of mathematicians, programmers, engineers, and computer scientists tackles everyday challenges like developing trading strategies, optimizing systems for minimal latency, saving and processing large volumes of historical data.

Working at Pinely demands exceptional C++ coding, algorithmic thinking, and mathematical intuition, attracting top talent, including winners and awardees of such competitions as ICPC, IMC, HITB PRO CTF, Google HashCode, etc.

Prizes: The top 30 contestants will receive a branded plush pine tree!

• +503

By ZhouShang2003, history, 4 years ago,

As we all know, a coder with A rating has a 1/(1+10^((B-A)/400)) probability of accepting a B difficulty problem.

At present, the following situations may occur: Two equally difficulty problems have a difference of 14.3% in acceptance rate; Two problems with a difficulty difference of 100 have the same acceptance rate. Accurating difficulty to units can reduce errors to 0.1%.

Codeforces Beta Round #23 has only 765 participants, Codeforces Global Round 9 has 21150 participants, so we can definitely make difficulties more accurate by using participants that have increased by more than 25 times.

By the way, would not it be better to have the same accuracy of rating between the problems and coders?

• +51

By ZhouShang2003, history, 4 years ago,
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