DWITE Online Computer Programming Contest, December 2010, Problem 1
When talking about points on the Cartesian plane, most people tend to deal only with points with integer coordinates (i.e. points whose and coordinates are integers). Given a line segment with integer coordinates, you are curious about how many points on the line segment (other than the endpoints) have integer coordinates.
The input will contain 5 lines, each line having 4 integers , where describes one endpoint of a line, and describes another.
The output will contain 5 lines, each line containing the number of points along the line (not including the endpoints) that fall on the integer co-ordinates.
0 0 2 2 -1 -2 1 1