pulsatio's blog

By pulsatio, history, 19 months ago, In English

Peru has participated in the IOI for the first time and has won a bronze medal. (orz NRolly)

I am the coach of the whole team and we will probably qualify again next year. Our goal now is to get a silver medal in the future. That's why I would like to know how is the training in other countries. How many hours do you dedicate to training? How many contests do you simulate per week? Do they enter codeforces, codechef, atcoder?

Clearly getting a silver medal is not easy but we want to try.

We will be grateful for your support. Best regards

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19 months ago, # |
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In Poland, we rely primarily on high schools and contestants themselves. Some prestige schools run regular classes on algorithms and data structures. I used to be a teacher in one of such schools and got 2-4 hours of classes weekly. During the classes, we were exploring basic topics (starting from binary search, through segment trees to centroid decomposition). I also gave them a lot of homework in form of problems from old competitions, and once or twice a month a full 5-hour contest. I encouraged people to participate in Codeforces and AtCoder, but as the IOI problems are significantly different from the problems from these platforms that was not a hard requirement at all. Everything that I said is just required to get to the final stage at the Polish Olympiad and then be selected to the IOI. After that, the ball was in the contestant's court. I still tried to help them by providing interesting problems from which they can learn something new, but it mostly depended on them. The Polish Olympiad helps a bit -- we have a summer training camp, but that's mostly it (unfortunately).

The one piece of advice I can give to you is you have to make sure that the students are motivated. It doesn't matter how many problems you have solved. You have to be passionate about problem-solving and have some fun doing it. It helps a lot when you form a group of people that can learn together and compete against each other.

Hope that helps!

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    19 months ago, # ^ |
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    Thank you very much for answering!

    In those classes, only you taught? That is, the students only had theory class 2-4 hours a week?

    I'm not sure if it's correct to ask the following but... How was the training after qualifying to the IOI?

    Finally, how can I improve as a coach? Honestly, several times I feel that I am not qualified for this job.

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      19 months ago, # ^ |
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      In those classes, only you taught? That is, the students only had theory class 2-4 hours a week?

      Yes. For some time I shared these classes with one more person (I had 2 hours and he had another 2).

      How was the training after qualifying to the IOI?

      Mostly I was suggesting to them problems from old national/international olympiads. Very rarely was I also needed to find/come up with a solution to some problems.

      Finally, how can I improve as a coach? Honestly, several times I feel that I am not qualified for this job.

      Don't worry, everyone experiences impostor syndrome. But I have to say that I also learned a lot about how to teach by preparing for the classes and even during them, just by practice. It also helps a lot to also watch other teachers, even by checking out some YouTube videos. Estoy seguro de que estas en el top 3 de los mejores maestros posibles en tu pais!

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        19 months ago, # ^ |
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        Thanks for all the tips. I am really grateful to you and the cf community. I appreciate you very much

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    19 months ago, # ^ |
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    Soooo hard :/

    Just go to the gym (the real one, not CF gym) and do the power trainings. Year after the teammates will be so strong, that will easily steal 4 golds from Chinese members XDDDD.

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19 months ago, # |
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Do CNOI.

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    19 months ago, # ^ |
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    Do they have English translation?

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      19 months ago, # ^ |
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      Some of the translations can be found in https://hydro.ac/p. Just search for "CSP-J", "CSP-S" and "NOI". (sorted in difficulty)

      If you need only the problems in CCF-NOI series, use https://hydro.ac/d/ccf/p. The problems with English names are translated to English.

      Sadly, only a small amount of the problems are translated to English. The organisers of HydroOJ are still working on this. You can use translation software for temporary use.

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        19 months ago, # ^ |
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        47 / 5.000 Resultados de traducción Are the editorials published somewhere?

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          19 months ago, # ^ |
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          Editorials are published on other sites, and are mostly in Chinese. You can see others' codes in Submissions or google for editorials in Chinese.

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19 months ago, # |
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Hi, I participated in this years IOI. I didn't win any medal, but right after every contest I knew a lot more solutions to subtasks which would eventually have led to a silver medal. The thing I lacked the most was time management and 5h contest experience. I didn't train more than 1 to 2 hours a day.

I'd suggest for future trainings to let the students get used to these kind of contests and also let them feel when they should stop thinking of a problem and go to the next one.

I hope this helps :)

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19 months ago, # |
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Hi :)

I won a silver medal in IOI this year, and in fact, the entire Australian team won silver medals. In order to win a silver medal, at least for this year, I think you just have to be consistent at not missing any easy subtask. For example, if you look at my profile, you'll see that I didn't solve any hard subtask (or any problem in full), but I got the majority of the easy subtasks, which was enough for silver. I don't think any of the subtasks I solved would be above 2100 difficulty on Codeforces. Therefore, I would recommend training for consistency — you don't have to be able to solve extremely hard problems (although that would make things easier), but you do have to be very consistent. Also, your implementation speed must be decently fast if your strategy is to focus on getting all achievable subtasks.

In terms of training, as usual, more practice = better results. Personally, I am a huge fan of DMOJ. The site contains thousands of problems, including both original problems as well as problems from common olympiads (e.g. IOI, APIO, CEOI). Compared to Codeforces and Atcoder, the site is definitely more OI orientated, with the majority of problems having subtasks similar to that in IOI. I would also recommend doing the contests — although less frequent, I feel that the problem quality is usually very high, and it is a good opportunity to practice getting subtasks on the harder problems. Of course, you shouldn't just do these sorts of contests, but also 5-hour virtual IOI-style contests. Personally, I did about 10 5-hour mock exams right before IOI, and that was enough.

In terms of theory, I don't think getting a silver medal is that different to getting a bronze medal. If you know all the basics with difficulties <= that of segment trees, then you should be fine. If you don't know them, then I found using the CSES handbook and problemset very useful.

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19 months ago, # |
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Shoot for the moon. Even if you miss, you'll land among the stars.

So try to get gold, then you will get your silver

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    19 months ago, # ^ |
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    It doesn't work.

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      19 months ago, # ^ |
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      just pee more during contests smh... worked for me

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        19 months ago, # ^ |
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        I still wonder how you got silver despite going to the toilet $$$16$$$ times during the contest.

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          19 months ago, # ^ |
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          hydrate pee repeeat

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    19 months ago, # ^ |
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    It's about the same vibe as "in order to become master, try becoming grandmaster"

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    19 months ago, # ^ |
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    I think this may not actually apply to IOI?

    For (low) silver, a good strategy is to go for all the easier subtasks, so it is not wise to spend too much time thinking about the full solution to a problem which seems hard. However, for gold you may actually have to go for 100 points at some problems, so it is probably the right strategy to invest time thinking about full solutions at the risk of not having enough time for scraping subtasks if you end up not finding the solution.

    So aiming for gold requires taking risks which may result in not even getting silver, while aiming for silver allows for safer strategies.

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19 months ago, # |
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I would like to share two wonderful underrated blogs written by E869120. Without that, probably I wouldn't able to get silver :)

In this blog, he discussed about the strategies which I think played the most important role. Regarding skill, he mentioned it's (should) enough to be around the purple-yellow range to get a silver.

About improving skills on codeforces, there is another blog by him.

For further practicing OI problems, OI Checklist probably has the best collection of problems.

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19 months ago, # |
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Hi, I'm Leonardo Valente from Brazil and I got silver medal this year. In my case, my school has training for olympiads, and im on the informatics olympiad training since i got into high school. In the months prior to IOI, my schedule was something like this after classes were over:

Monday: mostly school related stuff Tuesday: IOI vc, 2 hour coaching session afterwards Wednesday: another 2 hour coaching session Thursday: 4 hour coaching session + 4 hour class Friday: 4 hour mostly implementation practice Weekend: mostly resting

In the month before IOI we also had training camps (both one provided by our school and another provided by the brazilian OI).

Our coaches were particularly helpful to me, they went over a lot of stuff about contest strategies and hints that genuinely helped me during the contest.

Brazil got 3 silvers and a bronze this year, and I can assure that the entire brazilian team put in a lot of work as well.

Hope that helps!