Блог пользователя sevenkplus

Автор sevenkplus, 13 лет назад, По-английски

Team member: chnlich scottai1 zpl2 sevenkplus

YuukaKazami failed on one physics problem on day 1. s-quark failed on one string problem on day 2. (He implemented suffix automaton, with a little issue. )

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13 лет назад, # |
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Any problemset\standings available ?

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13 лет назад, # |
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Yep. Maybe it's time to create topic with IOI participants and their nicks on CF and TC?

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    13 лет назад, # ^ |
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    Has Russian IOI team been already selected?

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      13 лет назад, # ^ |
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      As far as I know, there will be summer training camp, where our national IOI team will be selected.

      Of course, there are not many candidates now :)

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      13 лет назад, # ^ |
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      It'll be finally selected at the beginning of July.

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13 лет назад, # |
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There were only two contests?

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    13 лет назад, # ^ |
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    There are also some tests focusing on the contestant's overall quality.

    And, there are several rounds.

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      13 лет назад, # ^ |
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      Could you tell about these tests? What is it like? Contests, yes/no tests or something else?

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13 лет назад, # |
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What is Physics problem? IOI's olympiad in informatics, isn't it?

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    13 лет назад, # ^ |
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    May be he means something like problem G (VKOSHP), where you need to know some physics basics to solve it?

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      13 лет назад, # ^ |
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      If so, it looks strange, because such problems usually doesn't require any skills except very basic school physics.

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        13 лет назад, # ^ |
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        It may be simple unluck, or may be this problem required some tricky algorithms except physics?

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        13 лет назад, # ^ |
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        Who cares about physics preparing for IOI selection?:)

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        13 лет назад, # ^ |
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        Indeed, it needs only basic school physics. But it seems that some contestants aren't familiar with it.

        The problem is: Given a tree-like resistive network in which all leafs are connected to ground. Every single wire is 1 Ohm.

        Modification: Add a power supply in one direction on one node. Query: The potential of one node to ground.

        N <= 5*10^4 longest chain of the tree <= 50 (to avoid some annoying precision issues)

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    13 лет назад, # ^ |
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    Sigh...The problem is look like that: Given you a tree-like electric network and put some source on it,and link the leaf nodes with the ground and assume the ground's potential is 0.

    the tree's max-length path is 50.

    And you're required to support two operations:

    1.put a source on a edge of tree. 2.query one node's potential.

    ...I'm no familiar with that kind of problems, some competitors get the the full score and I only get 20 points...

    Sigh...I think it's not fair to put that kind of problem with complex physical background in a OI-based contest....

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      13 лет назад, # ^ |
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      It's a bit strange that you know Kirchoff's law but do not know the voltage divider rule.

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        13 лет назад, # ^ |
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        I didn't figure out that each source are independent...I know the voltage divider rule that time...

        It's only a excuse for me...I would study physic harder next year...

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      13 лет назад, # ^ |
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      Yeah, it's a pity that IOI selection was decided on that :(

      But how come it's just one problem that decides who gets on the team and who doesn't? How many problems in total affect the selection?

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        13 лет назад, # ^ |
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        There two days in Chinese Team Selection Contest..

        And the score is calculated by the formula : your score/ max score *35.

        The first problem in day 1 is very hard and the third problem is relatively easy,so the result on day 1 is some how based on that physical problem T_T.The top 6 in the final standing all get 60 or more points on that physical problem.

        And the day2's problem are very easy...Many competitors get good result,although xujie get the 1st place in day 2 and I get the 2nd place in day 2...me ended 7th end 8th finally...

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          13 лет назад, # ^ |
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          Yeah, now I understand — it looks like the selection system is quite prone to this kind of thing happening.

          When I was a participant at the Russian IOI camps, there was about 12 days on average that decided the team, not 2, so it was much more stable and most gaps were more than one problem.

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            13 лет назад, # ^ |
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            In fact, we have 12 trials which each of the contestants write a problemset, and others tries to solve it. It is only worth 10 score. YuukaKazami got full score in this part!!!

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            13 лет назад, # ^ |
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            And there is also an assignment which is worth 5 score. YuukaKazami also got full score...

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        13 лет назад, # ^ |
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        Your final score in each day = you score / maximum score * 35. In day 1, the other 2 problems are not easy to get high score. So, knowing physics leads you to top 6. And the gap between contestants who can do the physics problem and those who can not is very large.

        TAT ...Why I have got negative votes...

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      13 лет назад, # ^ |
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      wo cao, ni men dou hui shuo english!!

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13 лет назад, # |
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Rough selection... :/

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13 лет назад, # |
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Congratulate for those who entered the national teams.... Maybe I can make it next years...Sigh...

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    13 лет назад, # ^ |
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    Don't be upset and be a true man, you certainly can make it.

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    13 лет назад, # ^ |
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    ...It is a pity that you have no chance to defeat tourist in IOI...

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    13 лет назад, # ^ |
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    How old are you and how many years left you have at high school? To be honest, I was thinking you're much older (at least, college student) judging by your high rating. Some time ago I've decided to read the code of the best contestants (top 10) after the contest to improve my performance and I've found your code is the most clear and understandable (along with rng_58 who is my 2nd favorite contestant) so it's even more surprising for me to know you're still at high school. Anyway, I wish you good luck next year — tourist is retired this year so you have chance to place top instead of him ^_^

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13 лет назад, # |
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Admire China team members!!! Wish their great success in IOI!!!

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    13 лет назад, # ^ |
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    How many years old that a Chinese student can become an IOIer? In some country, it's only 17 and 18 :)

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13 лет назад, # |
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Hi,

I think for Day 2 Q2, some formulae are missing. Could you please give us the complete problem statement for Q2? Thank you very much!

What I have gotten from the problem statement is that, you are given a set of points. Then all values within the convex hull of the set of points (including on the boundary) has value 1, while every other point has value 0. Then, you are given 2 sets of points, and you want to satisfy something.

May I know the full problem statement? Thank you very much!

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12 лет назад, # |
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ORZ FHQ!