DWITE Online Computer Programming Contest

December 2010

Problem 1

Integers along a line

When talking about points on the Cartesian plane, most people tend to deal only with points with integer coordinates (i.e. points whose x and y 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 file **DATA1.txt** will contain 5 lines, each line having 4 integers -1000 <= A,B,X,Y <= 1000, where (A,B) describes one endpoint of a line, and (X,Y) describes another.

The output file **OUT1.txt** 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.

Sample Input (first 2 shown):

0 0 2 2 -1 -2 1 1

Sample Output (first 2 shown):

1 0