From: Vance A Heron <heron@...>
Date: 2005-04-24T18:01:54+09:00
Subject: Re: Idea for Ruby Quiz - Su Doku solver

I wrote a solver in Ruby in about 2 hrs - not pretty, but it
works.  As mentioned by Christian, I used the same approach as
the 8-queens problem.  I'm using the int[][] notation...

Solving runs fast enough in ruby - no need for 'C'.  I find
it interesting to note the number of times you need to backtrack
in the puzzles rated "fiendish" difficulty. (In some, there
no backtracking at all!).

I'll think about a generator tomorrow - but it seems that much
of the "difficulty" is determined by *which* numbers you remove
from the answer.  I haven't spent much time playing by
hand, but I'm figuring the difficulty from a computer stantpoint
is directly related to the bactracking.  Looking at it, one might
be able to start recognizing patterns and make choices that require
less backtracking.

Vance


On Sun, 2005-04-24 at 02:34 +0900, Christian Neukirchen wrote:
> Florian Gro� <florgro@gmail.com> writes:
> 
> > Christian Neukirchen wrote:
> >
> >> Ruby doesn't provide a lot of support for 2d-Arrays
> >> and there is not a lot to abstract.
> >
> > What about NArray?
> 
> It exists, but where is the advantage over int[][]?
> 
> Anyway, I quickly wrote a Su Doku solver in gprolog, you can look at
> it here:
> 
>              http://rafb.net/paste/results/1ogo8j31.html
> 
> There are languages that have even less support for 2d-arrays. :-)
> 
> Happy hacking,