Bekmyrat.A's blog

COCI Contest #1
By Bekmyrat.A, 10 years ago, In English

This saturday (18.10.2014) at 14:00 GMT/UTC the 1st contest of the Croatian Olympiad in Informatics takes place.
You can login/register here(no registration for contest is required).
You can see the schedule of the year. Duration of the contest is 3 hours.
Gl & hf

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10 years ago, # |
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oh no,this contest overlaps with bayan.I think this time bayan should change his schedule. Edit:oh,sorry.I saw the date wrong.

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    10 years ago, # ^ |
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    COCI in on Saturday, Bayan is on Sunday. No overlap actually.

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10 years ago, # |
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In 4 hours...

Takin topic up, raising awareness...xD

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10 years ago, # |
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am I the only person who finds it hard reading the problem statements? how did they create this pdf document?

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    10 years ago, # ^ |
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    It is weird. If using Evince on Linux it is unreadable, and if using Adobe Reader on Windows all is ok.

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      10 years ago, # ^ |
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      Actually, is not. The text was not copy-able. It looked like a collection of images. This was annoying, since I usually copy the tests from the pdf.

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10 years ago, # |
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First contest without any scoreboard and just results from 1-3 sample test cases. That was ..interesting )

How long does it usually take to find out full results?

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    10 years ago, # ^ |
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    Personal results will be in like 30 minutes or even earlier. final standing of all contestants will be in a week or two (and solutions as well).

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      10 years ago, # ^ |
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      Cool, thanks!

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        10 years ago, # ^ |
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        Now you can see the hole result of the contest from this evaluator.hsin.hr/results link

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10 years ago, # |
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3 days ago... how come I didn't see this blog? I thought I check CF more often than everyone else combined...

Not like I'd have much time, though, with CTU Open today.

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10 years ago, # |
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Fast results!

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10 years ago, # |
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Those of who did solve, Could you please discuss the solutions. Preferably from task Piramida till the end. Thank You.

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    10 years ago, # ^ |
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    For problem Kamp:

    It is simple to solve if there is only 1 house.

    The total distance we travel is equal to twice the sum of all edges we travel minus the distance between the headquarter and the last house. Hence, for each node i, denote hi as the furthest house from i (it will be the last house we travel to). Let u, v be 2 houses whose distance is largest among all pairs of houses. It can be proved that either hi = u or hi = v. At a result, we can find the maximal distance from each node i to an arbitrary house by computing the distances from u and v to all other nodes.

    The remaining part is to compute the sum of all edges we use. We can first generate a set of edges and nodes that that are necessary to connect all the houses. After that, do an extra computation part for nodes which do not belong to this set.

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    10 years ago, # ^ |
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    Piramida:

    First, note that the zig-zag change in direction of the letters is irrelevant. Now, the thing you need to know for a requested row of the structure is which index in the string it starts with. It should be clear that the starting index (with indexing from zero) of the n-th row is , where is the length of the string. Now that you know the start position and the length of the sequence (which is equal to the row's index) — hence you can first add up all the appearances of the desired letter in the whole string a few times, and then possibly have some more letters left over to check. These can be added up using partial sums (summed for each letter individually). A trick to consider here, which cost me 30pts, is that all partial sums won't fit in the memory requirement, hence you need to first calculate all queries containing the letter A, then all the queries containing B, and so on, reusing the same 1D array as you go.

    Hope that was clear.

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10 years ago, # |
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For problem Mafija

I just implemented rand()%n and got 20 points :)

Because i couldn't understand problem

My submission

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10 years ago, # |
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Task pdf is very different

It's not picture or text file.

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10 years ago, # |
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I couldn't solve Zabava Please help me !

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10 years ago, # |
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can someone give me,code of 5th(ZABAVA) problem?

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    10 years ago, # ^ |
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    Here you go. Hint: the order of the students is irrelevant. We only need to know the final count of the students for each building. Let's say building i has ai students at the end and the people want to clean up the houses for a fixed number of times k. To minimize this value use the same technique as 478B - Random Teams.

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9 years ago, # |
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Did anyone solve Mafia with DP? How?

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