By Nerevar, 9 years ago, translation, In English,
Codeforces Beta Round #10 took place on Thursday, 15th of April at 19:45 MSK. This time I am the author of the problems. I would like to thank the creator of the Codeforces Mike Mirzayanov for correcting the statements and Julia Satushina for the excellent translation problem statements into the English.

I want to apologize for the problem D. There was a bug in model solution. Moreover, this problem may not be solvable in polynomial time even with such constraints on the number's size. We will investigate it. I hope nobody will feel offended in any case.

UPD: Now I am pretty sure that my model solution for the problem D was completely wrong. I want to apologize for it again. There will be no rejudge of the solutions accepted during the contest. The statement will be changed so that it will ask to find the LCIS of the two sequences. This problem definitely has a solution.

UPD: Problem D was changed as I promised.

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Announcement of Codeforces Beta Round #10
 
 
 
 
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By slycelote, 9 years ago, In English,

A. Die Roll

If the maximum of Yakko's and Wakko's points is a, then Dot will win, if she has not less than a points. So the probability of her win is (6 - (a-1)) / 6. Since there are only 6 values for a, you can simply hardcode the answers.

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By Alex_KPR, 9 years ago, translation, In English,

Hi, everybody, and welcome to the Codeforces Beta Round #9!

I'm its author. :) I've tried to make problems easy to read and funny. I’d like to say thank you to Mike Mirzayanov (for choosing problems for the contest and everything he’s done to organize it), to Igor Kudryashov (for checking author's solutions and making test generators), to Dima Matov (for correcting everything :)) and, of course to Julia Satushina (for excellent translations of the problems’ legends).

I'd like to remind you that if you have any questions on the problems, the best way to ask them is to use the web interface on the problems page.

I believe that the contest will be interesting to you, dear participants! I’m looking forward to seeing your suggestions here.

Good luck!

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By MikeMirzayanov, 9 years ago, translation, In English,
In case you are not familiar with the term, this the way of filling the site with content by the joint effort of the community. You might read a Wikipedia entry.
Basically, the idea to apply crowdsourcing to contests tutorials seems quite natural, but… it works badly. As you see, it is not the first time there has been no one willing to help the community. The question is: why and what is the way-out?

Let’s discuss it together. What should be changed/improved in order to make contests tutorials appear at Codeforces?

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By MikeMirzayanov, 9 years ago, In English,
Welcome and good luck on the round! 

I'd like to remind that if you have any questions on the problems, the best way to ask them is to use the web interface on the problems page. 

Later in the same post we will discuss the round. 

Wish you high rating,
MikeMirzayanov.

UPD. For contest you may thanks team Saratov SU #5, namely, users FeferGerald and Polichka.

UPD2. And better late than never: the presence of English statements we are obliged only to Julia. Many thanks to her for 8 wonderful translations of 8 rounds.

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Announcement of Codeforces Beta Round #8
 
 
 
 
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By MikeMirzayanov, 9 years ago, translation, In English,
The contest is rescheduled to start on 19:45.

Thank you all for participating in Codeforces Beta Round #7. I hope you enjoyed it. You may discuss the problems and system in comments. Please express your opinion, especially if you notice any inappropriate behavior. And as always, I will read with interest the suggestions for improvement.

From today on both-divisions contests ratings will be updated separately for each division. I. e. ratings will be calculated as if two contests (one per division) have taken place on the same problemset.

Also I would like to see someone who wants to write contest tutorial. This must be done in Russian and English languages. Of course you must solve the problem on either contest, or in the practice. If you have a desire to do it - write in comments. Your post will be published on the main page and later available on special link available from the contest page.

Many thanks to the contest problemssetters: RAD and e-maxx.

Good luck.

Ratings has been updated. Solutions are available for view.

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Announcement of Codeforces Beta Round #7
 
 
 
 
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By MikeMirzayanov, 9 years ago, translation, In English,
Welcome to the Codeforces Beta Round #6.

It will be good to see your feedback and impressions in the comments.

Wish you high rating,
MikeMirzayanov.

UPD. It seems the problem D has some tricky issues around judge solutions. Judge solutions will be fixed and the problem will be rejudged. If it will affect many participants, the contest will not be rated.

UPD 2. We have reduced constraints in the problem D and made rejudge. No solution passed tests. So the rejudge affected significantly only 4 participants, who solved it during the contest. But all of them increase their rating if we will count the contest as rated event. So we decided to make it rated and put problem with lowered constraints into the practice.

UPD 3. And by the way, the round tutorial is waiting for a volunteer. The tutorial should be in Russian and in English. It will be published on the homepage and later will be available via special link from the contest page.

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By MikeMirzayanov, 9 years ago, translation, In English,
Hello to everyone.

The latest news - now you are able to see the source code of the solution. During the contest you can view your own solutions only, but when the contest is finished you can view the solutions of any other participant. The table with the solutions is available via the problemset page, the solutions there are sorted by the program length. Pay attention, please, that you are free to change the sorting criteria using the option at the bottom of the table. 
There is another principle that gives you the chance to view the source codes of solved (during the contest or practice) solutions only. Personally, I regard the principle "everyone sees everything" as more suitable for our regular contests.  Am I right?

When you run a contest within your private community, you'll be able to set up your own principle for viewing solutions (or to switch off this function at all). But this functionality is under construction now. 

Wish you high rating,
MikeMirzayanov

UPD. Standings page is improved. You may double-click into a table cell (or use Ctrl+click) to view the submissions history.

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By MikeMirzayanov, 9 years ago, translation, In English,
Welcome and good luck on the round! 

I'd like to remind that if you have any questions on the problems, the best way to ask them is to use the web interface on the problems page. 

Later in the same post we will discuss the round. 

Wish you high rating,
MikeMirzayanov.

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Announcement of Codeforces Beta Round #5
 
 
 
 
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By at1, 9 years ago, translation, In English,

A. Watermelon

Only if w can be presented as 2m + 2k watermelon can be divided to two even parts.
So w = 2(m+k), where m, k1, that is
(w 4 и w - even) - necessary and sufficient condition for watermelon dividing.

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