Final round of Yandex.Algorithm-2015 will start tomorrow, on August 6, 2015 at 13:00 MSK. 28 finalists will compete for the total prize of 540 000 rubles.

Follow the contest on Yandex.Algorithm website.

**UPD** Congratulations to Yandex.Algorithm-2015 champion tourist! Second place goes to Petr eatmore takes third place

When did tourist not win onsite finals?

VK Cup 2012, IOI 2012.

By the way, I would not call this round 'onsite'.

Today.

FBHC 2013

All-Ukrainian Olympiads in Informatics 2015

For those who don't read Russian comments and didn't notice: there's virtual participation available now.

How to solve C if you can choose at most N/10 fractions?

I was wondering why this constraint was removed.

First version of the problem had no constraint related to powers of prime as denominators, instead it had N/10 and N was between 10^5 and 2*10^5 (and no readable sample, because of this limitation). For these N number of primes P(N) is not exceeding N ~ N/10.

With both of these constraints for small N, when P(N)<N/10 exists sets of fractions where such a selection is impossible.

Unluckly, some necroediting happened and constant was returned in the new version.

can anyone tell the difference between check sign and plus sign (on standings) ?

Check means OK after blind submission

It seems that for third year in a row Petr failed one of his "blind" submissions preventing him to claim the first place: 2013, 2014, 2015.

For third year in a row it is problem C :)

How to solve problem A?

I find a tutorial in the site:https://habrahabr.ru/company/yandex/blog/264253/,however it's in Russia.The English version translated is not clear.