The most popular Mathematical Olympiad in 2013,

The most popular Mathematical Olympiad in 2013,

As a Mathematical Olympiad problem, there is no solution, because the straight line is not thick and thin. Moreover, you can also prove from the angle of internal angle and that the graph can not be divided into two triangles. No matter who made it, even if it is a mathematical master, it is not considered. However, as a brain sharp turn, it is to draw a line thick enough