On Tue, Nov 11, 2008 at 12:34 AM,  <brabuhr / gmail.com> wrote:
> On Mon, Nov 10, 2008 at 12:25 PM, Matthew Moss <matt / moss.name> wrote:
>>> ## Sudoku Generator (#182)
>>>
>>> _Quiz idea provided by Lloyd Linklater_
>
> I haven't take the time to look at difficulty level, but have a very
> naive generator; the basic idea is to generate a puzzle using a sudoku
> solver and then punch some random holes in it:
>
> 72.times{puzzle[rand(81)] = 0}

Hmm, changed that while I was messing around with it, originally:

64.times{puzzle[rand(81)] = 0}

Since, it appears that any (unique) Sudoku puzzle must have at least
17 given numbers:

http://people.csse.uwa.edu.au/gordon/sudokumin.php

(Though, I take no effort to ensure that the at-least 17 numbers left
will lead to a unique solution.)