The Viking Battle was fought in 2013 and 2014 between the
teams for the International Mathematical Olympiad from Denmark,
Finland, Norway and Sweden during their joint preparation for the
olympiad, the IMO-Camp. In 2015 the team from Iceland joined
the battle. It has an individual and a group part, each with an exam
lasting four and a half hours. The number of problems in each part is
three and sixteen, respectively.