goadf90a's blog

How difficult are the BIO R2 Questions?
By goadf90a, history, 13 months ago, In English

I am 17 and I am preparing for the British Informatics Olympiad. When I try the BIO R2 questions, they don't seem all that difficult. Could someone please take a look at the BIO R2 questions (https://www.olympiad.org.uk/papers/2023/final/round_two.html) and tell me the difficulty level (in codeforces rating or smth). Apologies for the inconvenience.

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13 months ago, # |
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As someone who took part in BIO R2 this year, most of the problems seemed quite accessible (especially in the 5 hours you have to solve them). Although, as far as I remember no one came up with anything better than trivial brute force for the "hats" problem during the contest, despite the organiser thinking it was one of the easier ones. I'm not sure what they would translate to in Codeforces rating but if they don't seem all that difficult to you then it should be fine.

Although, I would advise against glancing over or just "mind-solving" past questions and underestimating their difficulty. In preparation for the 2022 R2 I thought of algorithms for many old problems and thought I would be fine, then when it came to the actual contest I found myself struggling with implementation. A couple things to keep in mind for BIO R2 is that you only get 5 submissions for each problem, so it is important to write correct code the first time, and full solutions are highly valued so one AC is better than two nearly-complete solutions. In the month before the contest you get access to a grader with many previous round 2 problems on it which I highly recommend practicing with.

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    13 months ago, # ^ |
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    Thank you very much for answering the question! I am guilty of "mind-solving" past R2 problems, as I can't find test cases for the problems. Would you know how many problems (for 2023 e.g.) need to be solved to make it to the IOI team?

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      13 months ago, # ^ |
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      The number of problems varies by year. In 2021, nobody fully solved more than 1 problem. In 2022 and 2023, everyone on the team solved at least 2 problems, though some who solved 2 did not make the team in 2022.

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13 months ago, # |
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It's terribly difficult, I had to take multiple sips out of my bo'oh'o'wa'er to solve the problems.

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