Блог пользователя MudoBog

Автор MudoBog, 11 лет назад, По-английски

Here are the results for Central-European Olympiad in Informatics.

Congratulations to winners!

1 Eduard Batmendijn Slovakia 355

2 Andrei Heidelbacher Romania 339

3 Ivan Lazarić Croatia 312

4 Jarosław Kwiecień Poland 282

5 Domagoj Bradač Croatia 249

6 Michał Zieliński Poland 246

7 Mihai Popa Romania 240

8 Martin Hora Czech Republic 238

9 Dominik Gleich Croatia 225

9 Mislav Bradač Croatia 225

11 Silviu-Emil Popescu Romania 208

12 Szilveszter Székely Hungary 202

13 Vendel Nagy Hungary 192

14 Barbora Kováčova Slovakia 188

15 Žiga Željko Slovenia 183

16 Eugenie-Daniel Posdărăscu Romania 179

17 Tonko Sabolčec Croatia 177

18 Benjamin Schmid Switzerland 176

19 Václav Volhejn Czech Republic 160

20 Marin Tomić Croatia 159

21 Friedrich Hübner Germany 153

22 Michal Punčochář Czech Republic 150

23 Patrik Zajec Slovenia 149

24 Kamil Rychlewicz Poland 145

24 Mislav Balunović Croatia 145

26 Mário Lipovský Slovakia 139

27 Vid Kocijan Slovenia 138

27 Kristóf Somogyvári Hungary 138

29 Mihael Peklar Croatia 130

29 Fabian Lyck Switzerland 130

31 Moritz Hilscher Germany 128

32 Philip Wellnitz Germany 120

33 Manuel Gundlach Germany 113

34 Timon Stampfli Switzerland 108

35 Filip Koprivec Slovenia 105

36 Ambrus Weisz Hungary 104

37 Michal Bui Truc Lam Slovakia 90

38 Jan Ludziejewski Poland 72

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11 лет назад, # |
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And what about medals ?? O.O
P.S. it would be nice if you add results to a table.

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    11 лет назад, # ^ |
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    The results are also on the competition site: day1, day2, total.

    I guess the medal cutoffs will be around 160 (bronze), 225 (silver) and 3rd or 4th place (gold).

    I'm surprised at the low score of all contestants on "adriatic" from day2, though. I found a 60pts solution really easy and a 100pts one well possible to do in time.

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      11 лет назад, # ^ |
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      Could you give some explanations about your solutions?

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        11 лет назад, # ^ |
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        "board" has an solution: first, you need to convert the string to path consisting of "1"s and "2"s only; for that, use stack, in which you remember sequences of consecutive ones and twos; "U" is removing the last number from the last sequence, "1" and "2" is adding it to the last sequence, "L" is removing all "1"s from the end (let there be K of them), replacing the last "2" by "1" and adding K twos, and similarly for "R". It's clear that the best solution is going greedily upwards from both nodes to some (the same) level, and then just moving on that level; also, it always fits into an integer, because the level we go to is at most the root (length equal to sum of depths of initial nodes). So, try all levels from the root downwards, re-calculate the horizontal distance between that level's ancestors of the initial nodes (it's just a number in binary), if it's clearly too large then break (to avoid overflow), and choose the best answer of "horizontal distance + sum of levels of initial nodes — 2*current level".

        Adriatic: draw a picture of what areas on the grid contain only islands of distance d. For d = 1, it's 2 non-intersecting rectangles touching the north-west and south-east corners of the map. For d = 2, it's the whole map minus 2 rectangles touching the other 2 corners, and not intersecting, and it's easy to show (by drawing it) that for any larger d, it's just some 2 smaller rectangles. How those 2 rectangles change depends only on the island with the largest/smallest x/y coordinates of those with distances d and less, which we can pre-compute in the same way as prefix sums (60pts is simulating this progress, then) and in a similar way — dynamic programming, in fact — we can count the sum of distances for any rectangle. Time is O(25002 + N).

        Codes: board (be warned, it contains other stuff like bruteforce and random number generator, because no feedback), adriatic

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          11 лет назад, # ^ |
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          I was told that Baklažán (Eduard Batmendijn) finished his 100-point solution of Adriatic during analysis mode in about 10 minutes. I.e., he was 10-15 minutes short of having a perfect score on day 2. Quite impressive :)

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      11 лет назад, # ^ |
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      If I didnt make silly mistakes, I would have 262. But I have 207. :(
      And I wonder are the participants bests of their countries? I first thought something went wrong in onsite contest, but as in newsletter everything was ok.

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        11 лет назад, # ^ |
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        For Slovakia the answer is no. Well, yes, Eduard is currently the best one we have, but the rest of the IOI 2013 team did not take part. We usually send younger students to the CEOIs. All four Slovak contestants at CEOI 2013 are eligible to compete at IOI 2014 (if they succeed to qualify, of course).

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11 лет назад, # |
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And can we find results of online contest somewhere?