Re: Sudoku puzzle solver for Apple II

[dempson@actrix.gen.nz (David Empson)]

David Empson <dempson@actrix.gen.nz> wrote:

> Scott Hemphill <hemphill@hemphills.net> wrote:
> 
> > If you think that one's tough, try this one.  It's much harder, at least
> > for my algorithm.  I don't know where I got it, but I saved it under the
> > filename "hints17-2".  I have four files of the form "hints17-x", all
> > very tough, but this one is the worst:
> > 
> > ..1.2.7..
> > .5.....9.
> > ...4.....
> > .8...5...
> > .9.......
> > ....6...2
> > ..2......
> > ..6.....5
> > .....9.83
> 
> Not even symmetrical.  (Shudder.)
> 
> Interestingly my PDA was able to verify this one much faster. I don't
> have time to look at it now, but I'll get to it in a few days.

That was a doddle. I did it before I went to sleep. It took me about 15
minutes, though I did need one guess. The previous "evil101" was much
harder.

This "hints17-x" one might be harder for a simple brute force solution,
but not if it is solved logically.

-- 
David Empson
dempson@actrix.gen.nz