Hello, Codeforces!

Today I would like to tell you about new Codeforces feature: about groups. Now you can create a group , invite people into it, add members to group and organize contests inside a group.

Create a Group

Only Div.1 coders can create a group. Good reason to increase rating, right? If you have rights to create a group on the Groups page, it will be a special link. Except name, you can specify:

• description (feel free to use simple HTML)
• logo: it will shine on each group’s page!
• related to group website URL

Welcome to 2013-2014 CT S01E011: 2013-2014 ACM-ICPC East Central North America Regional Contest (ECNA 2013). The training duration is 5 hours. It is opened for teams as well as for individual participants. After the end you may use the practice mode to complete problem solving. Also it will be availible as a virtual contest for whose of you who can't take part today. Please, do not cheat. Only fair play!

It is possible that the problems will be too easy for some participants, it is possible that we will add some problems.

The registration will be available on the Gym page and will be opened until the end of the training. Be careful registering team: please, choose only whose members who will take part in the contest.

Please do not take part in the contest if you have already solved the contest problems before.

Good luck!

Hi all! This round is prepared by me, caustique, el_sanchez, KAN, malcolm. I thank Gerald, who has organised our work and helped us with tricky situations, MikeMirzayanov for the system of organasing contest Delinur for the translation.

I hope that all problems will be OK and everyone will find intersesting problem for him/her.

Winners:

div1:

1. lovelymoon
2. niyaznigmatul
3. cerealguy
4. ainu7
5. cgy4ever

div2:

1. dotato
2. netman
3. kybconnor_4

I apologise for the mistakes in statements. I will be more careful in the next time.

Hello everyone!

November 14, 19:30 MSK will take place Codeforces Round #212 (Div. 2), which was prepared by group of authors from Saratov State University: Artem Sedanov (FunkyCat), Sergey Sukhov (Serega), Olga Chikatueva (Helga), Dmitriy Zaycev (My-my).

We thank coordinator of Codeforces rounds Gerald Agapov (Gerald) for useful hints and Maria Belova (Delinur) for translation of problem's statements into English.

Good luck and high rating to all!

UPD1. In this round will be used dynamic scoring system (see here).

UPD2. Tutorial is published here.

UPD3. Rating is updated. We congratulate the winners who solved four problems:

1. CleRIC

2. i_must_learn_matan

3. Dshavn

4. gzh1998n

Hello from Egypt!

Welcome to 2013-2014 CT S01E010: Codeforces Trainings Season 1 Episode 10. The training duration is 5 hours, to be held on Wednesday, 13th of November, 16:10. It is opened for teams as well as for individual participants. After the end you may use the practice mode to complete problem solving. Also it will be available as a virtual contest for whose of you who can't take part today. Please, do not cheat. Only fair play!

It is possible that the problems will be too easy for some participants, it is possible that we will add some problems.

The registration will be available on the Gym page and will be opened until the end of the training. Be careful registering team: please, choose only whose members who will take part in the contest.

This time it is special, because this problem set will be the Egyptian Collegiate Programming Contest — ECPC 2013. The theme of this contest is Bakkar, a famous cartoon character from one of the first and most memorized cartoons in Egypt!

This contest is the result of the hard work of many people: Islam Al-Aarag (islam-al-aarag), Mostafa Saad (mostafa.saad.fci), Amr Mahdi (amr_mahdi), Amr Mesbah (Amr_Mesbah), Ahmed Abd Rabo (ahmed.abdrabo), Ahmed Hamza (Hamzawy), Ahmed Thabet (ahmed_thabet), Yasser Yehia (Yasseryahia) and me (amrSamir). Special thanks to Ahmed Aly (ahmed_aly) for his help.

This is the first time to publish the ECPC contest online and we really appreciate your feedback on the contest.

We hope you will enjoy the contest, as we enjoyed making it.

EDIT: An excellent editorial by Xellos can be found here.

Greetings to the Codeforces community!

I'm glad to announce that we again decided to introduce a round based on one of the programming olympiads for schoolchidren in Saratov. This time it is a round for participants from Division II. Round will start at unusual time for Codeforces: 12:00 MSK.

The problems were prepared by MikeMirzayanov and me, while Fefer_Ivan and Gerald helped us with writing alternative solutions.

Members of the first division can participate out of competition, as usual.

Scoring distribution is standard: 500-1000-1500-2000-2500.

UPD: tutorial can be found here.

UPD 2: The model solution for problem E (unfortunately, there were only one model solution) was incorrect. But, the answers for all pretests were correct. After the round we fixed the solution. All submits for problem E were rejudged.

UPD 3: Results are final, ratings are updated.

Hello!

Codeforces Round #210 will take place on November 10 at 21.00 MSK and I am the author of the problems.

This is my first round on Codeforces and I hope everything will be well. I would like to thank Gerald Agapov(Gerald) and Vitalii Aksenov(Aksenov239) for helping me to prepare the round.

Good luck!

UPD.

Score distribution in first division: 500-1000-1500-1500-2000.

Score distribution in second division: 500-1000-1500-2000-2500.

UPD.

Congratulations to the winners!

First division:

1. Egor

2. PavelKunyavskiy

3. scott_wu

4. Dmitry_Egorov

5. mmaxio

6. enot110

7. sevenkplus

Second division:

1. _ZigZig_

2. budalnik

3. Ilya_Yakovlev

4. Neodym

UPD.

Editorial

Hello,

I know that the news will upset some of you: the round was moved 1.5 hours forward and it will start on 17:00 UTC.

As for me — the reason is very pleasant. The round original time coincided with a sniper's accuracy with the celebration of my daughter's birthday. Oh, St. Dijkstra, Tatyana is 2 years old! Last week I did many changes in judging backend (around caching) and I don't want in case of some issues to have a choice — to have a bad round or to have a bad celebration. I hope you understand!

Also I'm sure that new time will be more comfortable for some of you.

Hope to see you on the round!

Welcome to 2013-2014 CT S01E09: 2011 German Collegiate Programming Contest (GCPC 2011) + GCJ 2009 R3 C-D. The training duration is 5 hours. It is opened for teams as well as for individual participants. After the end you may use the practice mode to complete problem solving. Also it will be availible as a virtual contest for whose of you who can't take part today. Please, do not cheat. Only fair play!

It is possible that the problems will be too easy for some participants, it is possible that we will add some problems.

The registration will be available on the Gym page and will be opened until the end of the training. Be careful registering team: please, choose only whose members who will take part in the contest.

Good luck!

Hello!

Soon (on November 2 at 12:00 MSK) you are lucky to participate in Codeforces Round #209 for Div. 2 participants. Traditionally, Div. 1 participants can take part out of the competition. Pay attention to the round begining time!

Problems have been prepared by me. I want to thank Gerald Agapov (Gerald) and Ilya Los (IlyaLos) for help in preparation of this round, Mary Belova (Delinur) for translation of statements, Michael Mirzayanov (MikeMirzayanov) for marvelous Codeforces and Polygon systems.

UPD1: Scoring will be next: 500, 1000, 1500, 2500, 2500.

UPD2: Congratulations to winners!

1. cptbtptp
2. FancyCoder
3. Oyk
4. E.B.
5. orzkbc

UPD: Editorial

Good Luck!