From the Codechef website: "CodeChef is a global programming community. We host contests, trainings and events for programmers around the world. Our goal is to provide a platform for programmers everywhere to meet, compete, and have fun. CodeChef is a noncommercial organization operated by Directi, an Indian software company based in Mumbai, India."
Here's a profile from Korea Today magazine about two contestants from North Korea who joined the contest and did pretty well:
As a contest where the winner is decided by the accuracy of the answers given to the presented ten questions within 240 hours, the Codechef program contest is one of the world's top three internet program contests. In this contest the students of the Kim Chaek University of Technology won three consecutive victories in March, April and May this year. They were Ryu Song Chol, 21, and Mun So Min, 22, who are the program science circle members of the university which is leading the vanguard of the country's science and technology.
With the intention of bringing glory to their university on the world arena, they waged an intensive brain war from the beginning of the March contest. After solving all questions in an instant, they were confronted with the last challenge question. It was to find N points on the secondary degree plane to satisfy any condition. Most participants in the contest tried to tackle the question only from the mathematical angle, but Ryu Song Chol correctly grasped its character and drew up his algorithm by applying the law of elasticity tactfully. So, even by the end of the contest, other programs presented online did not reach the level of his frist program submitted when he set about the question.
The contest allowed renewing the solution 500 times, but Ryu only renewed it 200 times to come closest to the target value and gained the highest marks. Mun So Min came out second in the contest with 250 renewals. Then, Mun made another exertion and won the April contest. The most impressive contest for the participants and spectators was the May contest. Ryu Song Chol, who had stayed at the top for all the time in the contests dropped to third place just a day before the end of the contest. This proved that his rivals were never to be slighted. In fact, Ryu solved nine problems in a short time after the contest began, opening up the way to the first place.
Ryu said, "during the contest, I only thought of winning first place. It was not necessary to have much time to get through the contest successfully. The awareness that we represent the country's level of sci-tech development inspired me with original ideas."