In the evening, I went to the opening of the
exhibitionMixed (up) at B93 with photographs by Esmee van Zeeventer and Patric
Jonkman. I talked a bit with Esmee and told her that I am interested in
buying a copy of the (small) book she wants to make with some of her
photographs. I also talked with one of her former teachers about photography
and art.

I am working on a program for generating mazes and I wanted to implement an
algorith to check if a maze is 'nice', meaning that from every 'room' you can
reach any other 'room' and that there is exactly one route between any two
rooms, or in other words, that you cannot walk in a circle. (In graph theory
the nice maze is similar to a tree graph.) I was thinking about all kinds of rather complicated
algorithms to check these properties, until I realized that there was a very
simple algorithm. This algorithm depends on the property that you can walk
through a maze by following the wall on your right (or left) side. With a
closed maze, you will return to where you started. If the maze is nice, you
will visit every passages (between two rooms) in both directions. The number
of passages for a nice mazes is one less than the number of rooms and thus
easy to calculate. If the maze is not nice the number of passages you pass
while following the wall will be lower than twice the number of passages. If
some rooms are not reachable from each other, you will not visite them during
the walk, and thus the number of passages you count will be lower. If all the
rooms are connected, but you can walk in a circle, than you will never be able
to walk around and touch all the walls, meaning that you will only follow some
passages in one direction and not two directions. Thus the number of passages
you pass will also be lower.
This months interesting links