Please meet my today's guest Anatoly ruban, PhD in Physics and Mathematics, who yesterday participated in his 700th contest on Codeforces.
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-Hello Anatoly
-Hello Natalia

-Were you surprised by my message that you had taken more contests on Codeforces than anybody else?
-No, I wasn’t. I knew it for sure. There have been only several occasions when I missed rounds because of high rating, I think, not many than 20-30.

-Do you feel something special about contests with the round number like 500th, 600th or this one 700th?
-No, I wouldn't pay any attention if there were no interview.

-How did you start on Codeforces?
-Since 2001 (long before Codeforces) I have coached the competitive programming team of SibSUTIS — Siberian State University of Telecommunications and Information Science and created problems for All-Siberian Olympiads. When my students told me that a Russian-language analogue of TopCoder had appeared with support of Pascal I registered there.

-You have been so many years on Codeforces, your life must have changed in so many ways, how have you managed to find time for contests under so different conditions?
-My life has not changed much for more than the 10 years that I have been with Codeforces. Both the place of work and place of residence are the same. I still teach math at SibSUTIS and Novosibisk State University and coach the SibSUTIS team. And starting time suits me very well, usually it is 21:35 in Novosibirsk.

-Do you compete hard with your students on Codeforces?
-No, I don’t. Firstly, I do not take it too seriously. I believe if I take it seriously, I will compete quite successfully with my best students. Though you really need knowledge of discrete math for competitive programming and I am specialized in non-discrete, let's say, continuous math. Anyway, it is easier to discuss contest problems at training session after taking part in the contest.

-So Codeforces is your base site, isn’t it?
-Yes, it is. There is a lot of functionality there, useful services. It is not always reliable, I remember Codeforces having been down during our Olympiads but we were lucky to find the way out.

- Are there any issues because of using Pascal?
-I tried several times to migrate to C ++, but I still don’t like some features. There are of course much more advantages, but there is force of habit. I need to dive in C ++, and that is what I'm going to do at the training camp — as soon as I manage to organize them.

-What type of contest problems do you like more?
-My favorite topics are geometry, physics and math, “continuous math”. The more double the answer is, the more I like the problem. It is both a joke and a truth. Accordingly, I create mostly such types of problems myself.

-Oh, my god, what is a physics problem in competitive programming?
-Physics problems is a rather rare type in Olympiads programming, I would say, unreasonably rare one. You can find my problems in training section for the All-Siberian Olympiad on NSU site. Their authors are not indicated, they are result of cooperative work of jury team, but all the problems with stories from books by Ilf and Petrov are more or less connected to me. This is the site of the NSU Olympiads- you need to register there and then you can send solutions. It is sometimes down as well, but it helped us out. Everything is in the training section. There is not very convenient navigation, but you can figure it out if you want.
Couple of problems (on Russian) can be found here.

-What is the best source of knowledge?
-The best source is communication with people who could explain what you are interested in.

-What about books and sites?
-First of all it is “Introduction to Algorithms” by Cormen and e-maxx.ru

-What would you recommend to Olympiads participants?
-Thanks to my former students, former members of our Olympiads team, I learned the difference between german and austrian chocolate, between beers from Germany and the Czech Republic, I discovered taste of Californian wine – it is incredibly tasty if you get used to it and much more. When my students visit me there are always many talks about places where they had been. Ivan Popryga described the south of Brazil as a respectable and safe place. I am very thankful to all of them for visiting and talks. I hope next generations will visit his former coach as well.