Planely Speaking
Background
Many problems in computer graphics come down to being able to project
three dimensional (think real world) images onto a two-dimensional (think
this monitor) surface. For this reason, it is valuable to be able
to determnie if a set of points in threespace are in the same plane. It is
well known that three points determine a plane, so the issue of points falling
on the same plane only arises when you have more than three points.
The Problem
Your program should decide whether four given points in threespace all fall on
the same plane. If they do, we will say these points are plainar, and if not
we will say these points are nonplainar.
Input Specification
The file POINTS.DAT will consist of lines of data. Each line will contain 12
integers, which should be interpreted as the x y and z coordinates of a point
in space. For example the input line:
1 2 3 4 5 6 7 8 9 10 11 12
indicates that the problem is addressing the four points (1,2,3), (4,5,6),
(7,8,9), and (10,11,12).
The last line will contain 12 zeros.
Output Specification
The output file POINTS.OUT will consist one word per input line, the
word PLANAR if all of the points are co-planar, and NONPLANAR if the points
are not.
Sample Input
1 2 3 2 3 4 -1 -2 -3 -2 -3 -4
1 2 3 4 5 9 -100 99 -1 50 50 100
1 1 2 8 1 9 -9 5 4 0 0 1
0 0 0 0 0 0 0 0 0 0 0 0
Sample Output
PLANAR
PLANAR
NONPLANAR
I don't know what contest this problem is from. The sheet is not labeled.