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By ArtDitel, 13 years ago, translation,

Contest discussion

### Problem А. Triangle

Pythagorean theorem, brute force

In this problem you should implement a function, which takes three points and checks whether they form a right-angled triangle. There are a lot of ways to do so, but the simplest one is using a Pythagorean theorem.

• +34

By RAD, 13 years ago, translation,

Welcome to Codeforces Beta Round #18

Authors of today's contest are Mike Mirzayanov, Edvard Davtyan and me. Thanks to Dmitry Matov for his help in statements preparation and Julia Satushina for translation of problems in English.

Good luck everyone!

• +35

By tourist, 13 years ago, translation,
Contest discussion

Problem A. Noldbach problem

To solve this problem you were to find prime numbers in range [2..N]. The constraints were pretty small, so you could do that in any way - using the Sieve of Eratosthenes or simply looping over all possible divisors of a number.
Take every pair of neighboring prime numbers and check if their sum increased by 1 is a prime number too. Count the number of these pairs, compare it to K and output the result.

Problem B. Hierarchy
• +30

By brainail, 13 years ago,
Welcome all to Codeforces Beta Round #17, which will be held 10 June (Thursday) 2010, 19:00 (UTC +4, Moscow time). This contest will represent I.
I would like to thank Mike Mirzayanov who made this contest possible, Artem Rakhov for helping to test authors solutions and for nice the translation of problem statements into English. Great thank Gennady Korotkevich for preparation problem, writing authors solution and nice idea's. Hope you will like the problems.

I hope that number 17 would be interesting for you!

You can discuss the problems here in the comments after the end of the contest.

UPD: Contest the ended, thank you all for participation!
UPD:
• English tutorial is available here.

Announcement of Codeforces Beta Round 17
• +31

By MikeMirzayanov, 13 years ago, translation,

This post contains few words and many pictures. I decided to publish statistics on Codeforces visitors for the past two months. Why? I believe that it might be interesting. I took pictures from Google Analitycs.

Codeforces was born little more than 4 months ago. During this time, we held 16 contests (though one of them was non-rated). There are more than 4000 registered users, and every day we get about 30 more. There are 1797 coders participated in the contests, many of them participate in our contests regularly. The average number of registrations for one competition is growing, and I want to believe that soon it will conquer psychological barrier 1000 users. Also codeforces social network is popular: more than 400 posts, almost 6000 comments. The leader of the hit parade of posts is this post, has collected to date 184 comments. Bravo, SkidanovAlex! And of course I say thank you to everyone who helped make the project: those who help in the development, who make the problems, translate texts and write the alternative solutions, participate in community life, and just take part in contests. Thank you!

Below you will find a few more pictures and statistics, the total traffic of about 250KB.

• +14

By RAD, 13 years ago, translation,

Good afternoon.

Today I am the author of problems. I want to thank the creator of Codeforces Mike Mirzayanov and Edvard Davtyan for assistance in the problems preparation and Julia Satushina for great translations into English.

I wish everyone advance to the first division!
Artem Rakhov

UPD: The contest is over, thank you all for participating!

• +27

By Shtrix, 14 years ago, translation,

Greetings, CodeForces users. CodeForces Beta Round #15 will be held today, 29th of May at 19:00 MSK. My name is Roman Iedmeksyi and I am lucky to introduce this problem set.

I would like to thank Dmitry MatovJulia Satushina and Mike Mirzayanov for well-coordinated work on this match. Also I would like to mention the contribution of Yaroslav Tverdokhlib in problems testing.

I am a student of Kyiv National Taras Shevchenko University. I started programming at school. As my first achievement I had taken third place in Ukrainian Olympiad in Informatics. Next year I’ve worked harder and was qualified to IOI 2009 selection. Unfortunately I had not enough experience to pass.

In this contest I wish you good luck and high results.

UPD contest extended by 15 minutes

UPD Codeforces team apologizes that during today's round the server was regularly unavailable due to different technical reasons. We will try to do our best to avoid similar situations on the upcoming contests. Our apologies for some mistakes in the statements. Because of these reasons today's competition results will not affect your rating.

Looking forward to seeing you at Codeforces Beta Round 16.

Announcement of Codeforces Beta Round 15
• +31

By MikeMirzayanov, 14 years ago, translation,

## The first information letter

### General information

From 2nd to 12th August 2010 Saratov State University runs an international student summer school in computer programming. Teams of three people and individual participants are invited to take part in it.

The school will take place in a picturesque place at one of Saratov resort centers on the Volga bank. The participants will be provided comfortable rooms for 2-4 people and meals three times a day. The resort center owns a beach and sport grounds.

The school curriculum includes lectures by Saratov state university coaches, joint trainings, problems tutorials and topical workshops. The curriculum is designed for younger university students who aspire to achieve high results at programming competitions.

The fees are 15000 RUR (~ 500 USD) for a person. Moreover, each team or an individual participant should bring a laptop with the support of WI-FI.

All interested participants and teams should register at http://acm.sgu.ru/sazanka-2010/ till 10th June 2010. Don't postpone the registration, as the number of participants we can take is limited.

You can get additional information by e-mail mirzayanovmr[symbol-at]gmail.com. As since the official language of the school is Russian, the registration requires knowledge of Russian. Also it is recommended to view this page in Russian.

• +6

By MikeMirzayanov, 14 years ago, translation,
Today's round is not quite usual. The participants of the first division can register on it and to participate out of competition. This round will be some alpha-testing for this functionality, but for the next div. 2 round you can expect a stable version.

This round prepared for you by: homo_sapiensJuliaNerevarand me.

I want a high-ranking
MikeMirzayanov
• +15

By KADR, 14 years ago, translation,

Let me introduce an editorial to Codeforces Beta Round #13. If you have any questions or propositions - feel free to post them in the comments.

• +27