Top Recent Blog Posts
By chokudai, history, 38 hours ago, In English

We will hold Sciseed Programming Contest 2021(AtCoder Beginner Contest 219).

The point values will be 100-200-300-400-500-500-600-600.

We are looking forward to your participation!

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By AhmadShahal, 41 hour(s) ago, In English

“Success isn't always about greatness. It's about consistency. Consistent hard work leads to success. Greatness will come.” – Dwayne Johnson.

Today, I have been able to complete a 200 days streak on Codeforces, Although I don't have that much of a high rating, I am getting better and I did very good in ICPC qualification contests.

If someone told me half a year ago that I will be solving problems for 200 days consecutively I would say stop this nonsense, but hey! I did it.

Wish me good luck as my next goal will be reaching Expert and a 365 Days Streak!

chrome-V5f-Jz-JV2-Vv
upload images

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By YouKn0wWho, 4 days ago, In English

Hey everyone, I am sharing my personal code library where I compiled almost all the important templates that you will need in CP (saying almost just for courtesy). Most of the codes are originally written by me and some of them are collected from others but modified in a cleaner way. Link: https://github.com/ShahjalalShohag/code-library

It took me around 4 years to complete the list. Maybe each line is just a line to you but to me it tells a story of the excitements I had while learning those stuffs, the sleepless but fun nights I had to seek knowledge.

Why am I sharing this library?
  • Just so that your learning path becomes a bit smoother.
  • Knowledge hidden inside my head or codes in a private code-library will be useless when I am dead, so it's better to share those among people before I die.

Also, you can make me happy(as in to pay me) just by upvoting this blog and giving a star to the repository.

I believe that my coding style is pretty clean and readable, and furthermore, a few problem links are attached to most of the codes so that you can practice those problems. Best wishes, my friend blobheart.

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By Macesuted_AB, 38 hours ago, In English

Hello. I am a developer from the HydroOnlineJudge team, and I want to collect opinions in regard of translation of problems.

HydroOnlineJudge is a Chinese online judge system, which contains over ten thousand problems written in Chinese (some were collected from other sites).

These problems have not received any submissions from other countries. We are planning to provide English translations to these problems for the convenience of foreign users.

I wonder whether this is a meaningful project (Will it be helpful to you?), since the number of problems to be translated is huge and we currently do not have enough translators. If you are interested in helping us or have any suggestions, feel free to send me a email ([email protected]).

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By calari6400, history, 4 days ago, In English

Alice and Bob are too smart so called coders.They have now figured out how to escape from Plagiarism. Mayank is struggling with with Plagiarism on codeforces now he wants to figure it out if his two friends Alice and Bob have applied the rule to avoid Plagiarism.

They can perform two type of operations.

  1. Change the variable names to any other lowercase Latin letters.

  2. Insert lot of commented code.

Sample test case:

Alice submission->link

Bob submission->link

Alice submission->link

Bob submission->link

Please Upvote if they followed the rule.

Note-I was wondering why the submission of same problem during contest of both players have not exceeded 10 minutes.

For more test cases open their respective profiles.

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By Qingyu, 36 hours ago, In English

As we know, USACO is a competitive programming contest primarily for secondary school students in the US. It offers a large collection of excellent problems, from the easy to the difficult. Many of the problems are educational and worthwhile as training material.

However, the official website only offers problems from as early as 2011, and older problems are hard to find. Some of the Online Judges, such as POJ and BZOJ, contain some of the problems, but they are not properly filed together, and it's difficult to find the corresponding solution and test data.

In this post, I will try to list all the USACO materials that I have found so far. Most of the materials come from some old websites, and thanks to the efforts of web.archive.org, we can check out old websites that no longer exist. In addition, many of the problems were used as training materials in the training of Chinese IOI teams about 20 years ago. These materials have been preserved and are available through some Chinese websites.

It is important to note that since some of the materials are from a single source, I cannot confirm that the content is the original one. Also this list is not complete, there are still a lot materials I could not find. If anyone has these materials and would like to share it, please leave it in the comments section.

Update: Thanks to cjoa for providing some additional materials. They will be added to the list soon.

USACO 2020~2021

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USACO 2019~2020

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USACO 2018~2019

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USACO 2017~2018

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USACO 2016~2017

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USACO 2015~2016

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USACO 2014~2015

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USACO 2013~2014

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USACO 2012~2013

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USACO 2011~2012

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USACO 2010~2011

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USACO 2009~2010

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USACO 2008~2009

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USACO 2007~2008

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USACO 2006~2007

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USACO 2005~2006

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USACO 2004~2005

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USACO 2003~2004

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USACO 2002~2003

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USACO 2001~2002

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USACO 2000~2001

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USACO 1999~2000

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USACO 1998~1999

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USACO 1997~1998

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USACO 1996~1997

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USACO 1992~1996

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By kostka, 25 hours ago, In English

Whether you’re looking to practice your coding, prepare for an upcoming interview, connect with a global community, or have some fun — Kick Start is here to help! Round F 2021 starts in less than 24 hours on September 18 starting at 17:00 UTC. You will have 3 hours to solve what you can during the round.

We are excited to announce we are now supporting PyPy3 and updated compilers and interpreters for several languages. You can find more information in the Platform section of the FAQ.

Hope to see you in Round F 2021!

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By Amir_Hossein_Farhadi, 17 hours ago, In English

And again the person who wrote the blog with long title wrote another blog with larger title :(.

MikeMirzayanov can you do something for this?

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By EasonCF, history, 22 hours ago, In English

Notice before reading: The definition of developed and underdeveloped in this article is only based on OI and has nothing to do with other aspects.

UPD: Huge thanks to Ariadne.w for wishing us good luck in tomorrow's CSP2021! Here I also wish all of the participants of CSP2021 best of luck and can get the grades you want. :)

It seems that some CF users are interested in CSP in China. Then I will briefly introduce the competition rules of CSP here.

CSP (Certified Software Professional) is a large scale OI competition that replaced the position of NOIp (National Olympics in Informatics in provinces) since 2019 in China. The contestants can register for Group J and Group S. The differences between the two groups is that the problems of Group S is more difficult than Group J.

The competition will be held in 2 rounds.

The first round is conducted in the form of written examination. You need to finish a set of test papers with a full score of 100 in 2 hours. You can only enter the second round if you reach the score line of your province. The question of the score line will be discussed later. The competition will only provide test papers and draft papers. You need to prepare for the stationary by yourself. And, certainly, you cannot bring any electronic product.

The second round is the on-machine competition, which is held by OI rules. The competition will provide a desktop computer. The system on the computer may be Windows 7 with NOI Linux virtual machine or just NOI Linux. Also, the competition will provide some draft papers to you. In addition to the above products, you need to bring your own stationery, and you can't bring any electronic products other than those provided by the competition.

For Group J, you are going to solve 4 problems in 3.5 hours. The full score for each problem is 100.

For Group S, in CSP 2019 and the previous NOIp contests, the on-machine competition is held in 2 days(usually on weekends). In each day, you need to solve 3 problems in 3.5 hours. The problems in Day 2 are usually harder than the ones in Day 1. Since CSP 2020, however, the competition is held in one day and you need to solve 4 problems in 4 hours. The full score for each problem is 100, as well.

After the competition is over, the first prize, second prize and third prize (some underdeveloped provinces may not set up the third prizes) are determined according to the score line of each province.

Finally, let's see the score line. The score line is different in different provinces. Some developed provinces, especially Zhejiang, generally have a higher score line than some underdeveloped provinces.

The following is the score line for the 1st prize of CSP-S 2020 in some provinces of China.

Click here to see the score line

P.S. As for NOIp, this competition was not held in 2019 due to CSP. However, Since 2020, NOIp is held again in the form of the first provincial team selection competition. It is held after the second round of CSP. You need to solve 4 problems in 4.5 hours and, of course, the problems are harder than CSP-S.

P.S.2 Here you can see the problems of CSP-S2019. Don't worry about the problem statements, as they've all translated to English.

P.S.3 NOI Linux was based on different system in different version. Specifically:

  • ? to 2021.10.21: NOI Linux 1.2 (Ubuntu 7.10).
  • 2021.10.21 to 2012.3.20: New NOI Linux (No version) (Ubuntu 10.10)
  • 2012.3.20 to 2013.1.7: NOI Linux 1.3 (Ubuntu 10.10)
  • 2013.1.7 to 2016.10.8: NOI Linux 1.3.2 (Ubuntu 10.10, Updated a little)
  • 2016.10.8 to 2021.7.16: NOI Linux 1.4.1 (Ubuntu 14.04 LTS)
  • 2021.7.16 to now: NOI Linux 2.0 (Ubuntu 20.04.1)

CSP started to use NOI Linux 2.0 since 2021.9.1.

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By galen_colin, 45 hours ago, In English

I wanted to make a video on a cool problem, which also happened to be the problem that let me become red. It also ended up turning into a story about that contest and what happened leading up to solving it, including baby trucks, broken problem difficulties, and traveling to the past to see mid-contest rankings. I think some here are interested in stories, so I'm posting this here for those who are. The video is here.

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