SAD_IN_NIGHTMARE's blog

By SAD_IN_NIGHTMARE, 5 weeks ago, In English

Let's discuss the problems of IATI(International Advanced Tournament in Informatics) 2024.

Day 1
Day 2
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5 weeks ago, # |
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https://infos.infosbg.com/home?lang=en

the problems, submissions of participants and standings of junior and senior group

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k1r1t0 orz

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when is closing ceremony?

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On the first day, the worst tasks of the seniors that I have seen. Maybe I think so, because before that I only participated in juniors.

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    5 weeks ago, # ^ |
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    Idk, to me they felt quite nice. (And definitely nicer than last year's iati tasks, for example)

    also I would say that when participating in IATI, you should be aware of how "specific" problems are =)

    In particular, day1A was very nice and interesting to play with, to me felt quite simillar to

    spoiler

    Day1B, while having a bit of messy implementation, had straightforward idea for 33 points (place "forced" bridges in bfs-like manner), and for further points it kinda told you directly what to do with grader's "TimePassed()" function.

    What I did was

    And well, only for problem C i can agree that matrix expo isn't IOI-syllabulus knowledge, but neither it is some extremely hard or advanced topic =) In rest problem wasn't that bad either (although not my favourite, yeah)

    But speaking of whole day1 problemset, I really can't call it bad. Problem A definitely was good and for problem B you can't complain that problem in programming competition required you to implement something :)

    (All said above is not meant to be offensive, just wanted to express my opinion on tasks, as I saw many people complain about them)

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The juniors had 4 tasks from competitors from the senior group!

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Is there a mirror/virtual where I can submit?

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The tasks given at the Junior section can be accessed on Kilonova

The senior tasks will be uploaded soon too.

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How is it even possible to solve junior day 1 B? Like you can only solve for L <= 16 with ceil(log2(n)) = 16 calls using binary search but to get full score you need to call it only once which for me seems impossible. Is it supposed to be hardcoded?

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I almost forgot. Congratulations on the bronze!

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This olympiad in my opinion had not the best problems and not the best TL(hate day 1 A,B, and TL on day 2 A), but I had some fun.

On day 1, I spent 4h out of 5 just grinding C to get AC using matrix exponentiation (got 81, optimized to around 0.9-1.2s, but TL is 0.7, which makes sense), and on day 2 spent 4.5h out of 5 just getting AC on A (really wanted to get full score, and quickly knew how to solve it), because TL was very strict for me (in fact I almost gave up, but at the end resubmitted my solution, which was previously working 1.012s to 0.994s).

Funnily, those two problems (81+100) were enough to get me silver (plus 27+7 on other two problems), so that's cool. I think I will take it more seriously next time, not grind one problem for the whole contest, and try to get much higher place.