> -----Original Message-----
> From: David Tran [mailto:email55555 / gmail.com] 
> Sent: Tuesday, August 23, 2005 3:49 PM
> To: ruby-talk ML
> Subject: Re: [QUIZ] Sodoku Solver (#43)
> 
> > Adam Shelly wrote:
> > ...
> > And it took a while to figure out that this one was unsolvable:
> > +-------+-------+-------+
> > | _ 2 _ | _ _ _ | _ _ _ |
> > | _ _ _ | 6 _ _ | _ _ 3 |
> > | _ 7 4 | _ 8 _ | _ _ _ |
> > +-------+-------+-------+
> > | _ _ _ | _ _ 3 | _ _ 2 |
> > | _ 8 _ | _ 4 _ | _ 1 _ |
> > | 6 _ _ | 5 _ _ | _ _ _ |
> > +-------+-------+-------+
> > | _ _ _ | _ 1 _ | 7 8 _ |
> > | 5 _ _ | _ _ 9 | _ _ _ |
> > | _ _ _ | _ _ _ | _ 4 _ |
> > +-------+-------+-------+
> 
> Euh ... mmm....
> my program tell me that is one has unique solution ( on 
> 16.672 seconds )
> +-------+-------+-------+
> | 1 2 6 | 4 3 7 | 9 5 8 |
> | 8 9 5 | 6 2 1 | 4 7 3 |
> | 3 7 4 | 9 8 5 | 1 2 6 |
> +-------+-------+-------+
> | 4 5 7 | 1 9 3 | 8 6 2 |
> | 9 8 3 | 2 4 6 | 5 1 7 |
> | 6 1 2 | 5 7 8 | 3 9 4 |
> +-------+-------+-------+
> | 2 6 9 | 3 1 4 | 7 8 5 |
> | 5 4 8 | 7 6 9 | 2 3 1 |
> | 7 3 1 | 8 5 2 | 6 4 9 |
> +-------+-------+-------+

Ok, I figured it out also...

solving nr 1     2.015000   0.000000   2.015000 (  2.016000)
+-------+-------+-------+
| 1 2 6 | 4 3 7 | 9 5 8 |
| 8 9 5 | 6 2 1 | 4 7 3 |
| 3 7 4 | 9 8 5 | 1 2 6 |
+-------+-------+-------+
| 4 5 7 | 1 9 3 | 8 6 2 |
| 9 8 3 | 2 4 6 | 5 1 7 |
| 6 1 2 | 5 7 8 | 3 9 4 |
+-------+-------+-------+
| 2 6 9 | 3 1 4 | 7 8 5 |
| 5 4 8 | 7 6 9 | 2 3 1 |
| 7 3 1 | 8 5 2 | 6 4 9 |
+-------+-------+-------+

but the other (wrong) version was so damn fast :)

cheers

Simon

p.s.: I vote for a new Quiz: 
find false answers to sodukus realy quick :)