ACM ICPC 2015 World Finals Results

It took them cumulative practice of at least 19 years to reach there.

(One of them started practicing 10 years ago [1]. The two other are active at topcoder since 2010 [2] and 2011 [3]).

[1] http://en.wikipedia.org/wiki/Gennady_Korotkevich

[2] http://community.topcoder.com/tc?module=MemberProfile&cr=229...

[3] http://community.topcoder.com/tc?module=MemberProfile&cr=230...

There is a meta-structure to the problems that people can and do train for. I dabbled in this as a student (part of the BCS UK-wide competition winning team in .. '99 or thereabouts). You basically need to memorise "Introduction to Algorithms" http://en.wikipedia.org/wiki/Introduction_to_Algorithms , have a good practice in writing microparsers and output-formatting code (usually scanf/printf will do, sometimes you need something a bit more complicated), and have the right kind of puzzle-solving mentality.

Like Project Euler, sometimes you have to find a conceptual shortcut because the brute-force solution isn't feasible.

The BCS format involved four people and one computer, so work discipline, coding on paper, and a sort of extreme pair programming were important.