First place was taken by Gennady.Korotkevich, also known as "tourist." He has a history of placing extremely highly in sport programming contests[0], is at the top of topcoder's algorithm section[1], and has had several articles[2,3] written about him.
I imagine there's a lot of practice involved, but I wasn't able to spot an interview that specified the exact amount of time tourist spends coding or studying algorithms every day.
Three to four hours of practice a day is quite a lot, in comparison Johnny Ho (http://www.quora.com/TopCoder/Who-is-Johnny-Ho) only did about 1 or 2 a day while practicing for IOI 2012
Source: me asking that exact question to him at IOI 2012
"Not more than three to four." != "Three or four hours practicing every day consistently"
Also, this guy has been performing at an extremely high level for years. If he didn't do any competitive programming practice at all for a year, I doubt you'd notice a big difference in his performance.
Some of the top guys at Topcoder Open / Google Code Jam don't even participate in matches outside of the yearly tournament and I doubt they are practicing consistently (i.e. once you get to that level at problem solving, performance doesn't seem to decay much and certainly much less than in a similar situation for athletes - though these guys are students / engineers whose brains are still being stimulated and solving other kinds of problems outside of competitions).
- How many hours a day are you in front of the computer?
- Not more than three to four. I like playing football and table tennis, so I try to find time for sports as well.
http://www.ioi2009.org/downloads/br8-3str-en.pdf