Hello everyone!

Welcome to the **Codeforces Beta Round #90**! I (Sergey Sukhov) and Alexander Ignatyev (ai9128429340875) have prepared for you today's contest. We thank Artem Rakhov (RAD) for help and useful hints, Mariya Belova (Delinur) for translation of statements, as well as Michael Mirzayanov (MikeMirzayanov) for opportunity to conduct this round.

Good luck and high rating!

**UPD**. Unfortunately the mistake was found in author's solution of problem B, therefore this round will be unrated. We present our apologies.

**UPD2**. Analysis of problems A-D is published.

. What is bad in ErzhanDS's comment?

I always downvote GL&HF messages. I hate them.

about topic(i.e. next contest now)here.Is wishing good luck bad at all??? Before any contest, any one can wish other good luck, this is like a love to all, or can be formality. But, why is this seems as down voted comment??? If anyone finds only useful info, then they only should search for that, not giving down vote to any comment which never seems like nonsense comment. Coz, every vote counts as contribution in Codeforces. So, we all should be careful of this.

One thing, please look at this Blog, writer written in the last "Good luck and high rating!". So, what will you say? Is it down voted blog????

But, may be this is not like what you are thinking, Actually I never think of this. Always saying Good luck before any contest to all the contestastent (online or onsite). As Topcoder gives us chance to chat, we can say Good luck to everyone by a General post, In codeforces, it give chance by comments. So, I don't think that saying Good luck is like begging for contribution. If so, then I will never say good luck. Coz, I don't like this types of thought like begging for upvoting.

I consider "GL & HF" messages annoying, that is the reason why I have downvoted it.

XD

Am i wrong?

But it can only be divide to 3 cards. So 1st and 2nd theorem can't form another card.

is problem B's description wrong or the author's solution wrong?

So even the pretest are wrong?

you can read other posts here.

runtime error(on case 5).I have worked on it but not finding the reason.This code is in JAVA.Here is the link.

You use nonexistent elements of array "c". The size of array "c" is "t", but "i" is running from 0 to "card".

But they wouldn't skip over them, because nobody is going to miss out on easy points, regardless of whether they are high rated or not.

i think its not right that contest is unrated , we can just ignore problem B and count points with 4 problems, for someone who wrote contest well is not fair not to update his rank , in all case authors are guilty not coders

Imagine someone who spent his time on solving B correctly and then got his solution ignored. Someone else could skip B or have an incorrect solution, and that gives him an unfair advantage...

i have 1528 rating, when i wrote 4th problem i was at 16 place, and i was happy and i thought my rank would be increased then authors wrote that round was unrated, is it my falt ?but at last my code had time limit at 28th test :(

I think it's funny how the tricky case in B is so easy to miss that even the authors of the problem themselves missed it ;)

If we count how many different theorems(not cards but single theorems) has Vasya seen then we can check that this number is lesser then (k*n/k) and this will do the job.

To calculate number of different theorems you can use a set, or an array as RiaD-WaW said.

The number of differrent cards is the number of different theorems divided by the number of theorems in a card.

sameset, and there won't be any theorem in two or more different cards, one could just pick any theorem i from a card (say, the smallest one) and set used[i] to true (where used is a bool array). The number of true elements in used will be also the number of different cards given.3 2

1 2 3

2

1

2

Answer is 1.00000000 2.000000000

Is that correct??? I think it should be 1.00000000 3.00000000.Please tell me if I am wrong??

You need to read better condition: "Besides, no theorem is mentioned in more than one card (that is, theorems won't be mentioned in any card)."

P.S. And that was previously stated!

Bashmohandes Gad:D:D :D