Re: [xsl] Sudoku - A solution in XSLT 2

[Eric Bréchemier <eric.brechemier@xxxxxxxxx>]

On 2/15/06, andrew welch <andrew.j.welch@xxxxxxxxx> wrote:
> (...)
> Any suggestions for improvements of the algorithm are
> welcome.
This is a fine piece of code; I have no real improvement to suggest,
only a few comments.

I tried the stylesheet on the "Extremely Hard" board, and
interestingly discovered it actually had several solutions, with both
my own sudoku solver and the Sudo Cue program giving the same
solution, and your stylesheet an original solution. The difference
lies in the resolution methods chosen, the order of the tests (1 to 9)
applied in your backtracking resulting in a solution with lower
numbers.

A second (general) comment is on how relative the notion of board
complexity is : everything is in the eye (I mean actual
knowledge/pattern matching capabilities) of the viewer. I found the
"Extremely Hard" board, in spite of the few givens, could be solved
using only two so-called "Basic Solving Techniques" (see Sudopedia
http://www.sudopedia.org/index.php?title=Basic_Solving_Techniques)
known as (hum) "Naked Singles" and "Hidden Singles".

I'd be glad to use parts of your transform in my own solver to apply
backtracking as a safety net once human reasonings have failed, if you
allow me to.

Best Regards,

Eric