thocevar's blog

By thocevar, 5 months ago, In English,

Central European Olympiad in Informatics 2017 will this year take place in Ljubljana, Slovenia from July 10 to July 15. I would like to invite you to an online contest featuring the CEOI task which we'll organize after the conclusion of the on-site contest.

The online contest will last 5 hours and feature 9 problems from the practice session and both competition days. It starts on Saturday, 15 July at 14.00 CEST (UTC +2). Registration will be enabled after the conclusion of the on-site contest on Friday.

The contest will be suitable for a wide range of contestants with the typical divison of problems into subtasks. With a relatively narrow time frame of 5 hours it should present a challenge even to the best. We're looking forward to your participation.

UPDATE 1: The onsite contest has concluded. You can check the results.

UPDATE 2: Registration on the online judge is now open. Good luck tomorrow.

UPDATE 3: Congratulations to demon1999 for winning the online contest and thanks to everyone who participated. We will upload the tasks, tests and solutions to the web page shortly.

 
 
 
 
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5 months ago, # |
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I missed this post before (and I believe I'm not the only.one), so let's put it on the sidebar once again.

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5 months ago, # |
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Isn't it a better idea to create two or three separate online mirrors (for both days and maybe practice)?

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    5 months ago, # ^ |
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    I agree, but we're short on various resources (mostly the manpower to monitor the contest), which is why we decided to pack everything into a single online contest. Despite this, we hope the contest will be a good experience for online contestants.

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      5 months ago, # ^ |
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      If someone's willing to hold a mirror (solving the manpower problem), would you agree with that? because this online contest (which you are going to hold) kills the point of a mirror contest it's like: "Hello guys here are the problems from CEOI, enjoy", not like an actual mirror contest which has the vibe of a real contest.
      I think others also agree with me (do they? if not say so).

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        5 months ago, # ^ |
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        The online contest is not intended as a mirror but as a separate contest featuring the same tasks. It will run as scheduled. After the conclusion of CEOI we will coordinate with CS Academy to set up the virtual contests of individual competition days.

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          5 months ago, # ^ |
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          Which puts us into a dilemma:

          Do I want to compete in the bigger online contest against other online contestants, or in a more authentic virtual contest against actual CEOI contestants (and other virtual ones)?

          For me it's resolved by the fact that I am busy on Saturday :D

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            5 months ago, # ^ |
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            Note that CS Academy does not currently support the simulation of the onsite contestants. So you would be competing against virtual ones. However, with IOI rules it's trivial to check where you would end up in the onsite ranking.

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      5 months ago, # ^ |
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      CS Academy staff said they are eager to organize mirrors(They already organized Balkan OI mirrors).

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        5 months ago, # ^ |
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        Yes, we're up for it, if the organisers agree.

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          5 months ago, # ^ |
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          That would be great idea. At least the problems will be accessible and they won't disappear immediately

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          5 months ago, # ^ |
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          Well let's hope organizers agree.

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          4 months ago, # ^ |
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          Where can I get an update whether they agreed and when the contest will be?

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            4 months ago, # ^ |
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            We just got access to the problems. If you didn't get a chance to participate in the official mirror you can try our contests on Thursday and Friday.

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4 months ago, # |
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Live ranking?

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4 months ago, # |
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+46 just for this blog?

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4 months ago, # |
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I tried registering and got: Registration is disabled in this installation of Putka.

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    4 months ago, # ^ |
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    "Registration will be enabled after the conclusion of the on-site contest on Friday." I'll post an update at that time to notify everyone.

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4 months ago, # |
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I tried to register in Putka evaluating system but I failed because I had this error: Captcha: This field is required. I can't see any on this page or even a field to type it. Here is a screenshot of my problem: http://imgur.com/6Vpvlqx I tried different operating systems and browsers: MacOS Safari and Windows 7 Google Chrome.

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    4 months ago, # ^ |
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    Sorry, I tried another link to this testing system and registration system showed a Captcha to me.

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      4 months ago, # ^ |
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      The exact same thing happened to me, so maybe something was fixed in the meantime (?)

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4 months ago, # |
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Can we solve the problems after the end of online contest? I mean for training?

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    4 months ago, # ^ |
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    Yes, the judge will stay available for a short time. Afterwards the tasks will be accessible for solving at CS Academy.

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4 months ago, # |
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write "road can even connect the city with itself"
do not put tests with such roads
do not write that graph can be disconnected
put such tests

To be frank, it was rather boring problemset. I do not know yet how to solve mousetrap, but rest is quite standard.

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    4 months ago, # ^ |
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    Not including tests with loops in the One-Way Streets problem was a minor oversight on our part. I think that making an assumption that the graph is connected is a mistake and shouldn't need an explicit clarification.

    The problemset was too easy as indicated by three full scores. However, with the exception of the top contestants it did rank the others just fine.

    Regarding the Mousetrap problem, you can calculate how many moves are required to get the mouse out of a subtree once it enters it. With this information you can use a binary search to determine which branches along the path to the trap you have to block to prevent the mouse from entering the corresponding subtree and force it into the trap in time.

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4 months ago, # |
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When the problems will be published on CS Academy?