[casual_games] Sudoku difficulty

[Robert Gordon]

Hey Charles - I'll bite.

I created this:
http://dailysudoku.shockwave.com

There's quite a bit of discussion out there on the right way to think about
this issue. One of the more interesting (and inspirational) solutions comes
from the developer of the Sudoku Susser (Google it). There are essentially
two ways to go about grading puzzles - one is to compare brute-force search
times across puzzles, the other is to employ progressively more
sophisticated human-logic solving techniques. My preference is for the
latter, and many seem to feel that this gives a more realistic rating.
There's a lot of information out there describing the techniques and I've
managed to code for 7 of them so far (more than enough to handle out
puzzles).

Now - that doesn't really speak to the generation issue. Generating 'good'
puzzles can be a very challenging task (apparently Gould from Sudoku.com
spent years perfecting his program). One strategy is get together a program
that simply spits out MANY valid and single-solution puzzles, then run them
through a rating algo to find the 'good' ones.

r o b


| Robert Gordon
| The Article 19 Group Inc.
| phone: 514.938.8512
| email: rob at article19.com
| http://www.article19.com


> From: Charles Parcell <cparcell at toxictoy.com>
> Reply-To: cparcell at toxictoy.com, IGDA Casual Games SIG Mailing List
> <casual_games at igda.org>
> Date: Tue, 14 Feb 2006 17:24:57 -0500
> To: casual_games at igda.org
> Subject: [casual_games] Sudoku difficulty
> 
> This actually is spawning from another list I am on where we are talking
> about Sudoku puzzles. the question has been posed, how do you rank a
> Sudoku puzzle as simple, or difficult?
> 
> We are discussing generators. The approach has been to generate a solved
> puzzle first and then remove numbers from there. In this removal process
> it is assumed that different formulas would be applied to generate an
> simple or difficult puzzle. There are two thoughts going on around this.
> First is the number of empty locations within a puzzle. The second
> thought is the number of start points for solving and "chaining" solutions.
> 
> Since this is a casual game list and Sudoku is a casual game... I assume
> that this is not an inappropriate e-mail.
> 
> Charles P.
> 
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