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From: Ian Kelly <ian.g.kelly@gmail.com>
Date: Wed, 25 Mar 2015 13:05:37 -0600
Subject: Re: Sudoku solver
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On Wed, Mar 25, 2015 at 12:44 PM, John Ladasky
<john_ladasky@sbcglobal.net> wrote:
> On Wednesday, March 25, 2015 at 4:39:40 AM UTC-7, Marko Rauhamaa wrote:
>
>> I post below a sudoku solver. I eagerly await neater implementations (as
>> well as bug reports).
>
> So, it's a brute-force, recursive solver?  The code is nice and short.  But I bet it takes a long time to run.
>
> I and a student of mine are working on Sudoku solvers which solve puzzles the way that humans would.  Smart, pattern-recognition strategies take less time to run... but, obviously, far more time to turn into code!

I haven't written one myself, but Peter Norvig has a nice example on
the web of a Python sudoku solver using constraint propagation to
limit the search space.

http://norvig.com/sudoku.html

I don't know that I would do it much differently if I were going to
write one myself.