From: Alpha Chen <alchen@...>
Date: 2005-08-26T21:30:37+09:00
Subject: Re: [OT] Sudoku again: How to find a sudoku?

On Aug 26, 2005, at 2:08 AM, Ralf M�ller wrote:


> What i like to know, is how could you know, that a sudoku-like  
> number table is
> a real sudoku with only ONE SINGLE solution?
>
> The Solvers from the quiz (which I did not read) will surely find a  
> solution.
> But where did the sudokus themselves came from?
>
> What about a sudoku-generator? Which leads to: How to proof a  
> certain number
> table has one and only one solution?
>

For those of you interested in pursuing some more Sudoku programming,  
there's a programmer's forum for it here: http://www.setbb.com/phpbb/? 
mforum=sudoku

I think most programs solve the puzzle by use of only logic, which  
would mean that there would only be one solution. Or if there must be  
guessing (using the Nishio method, I suppose), then you'd make sure  
that there's only one branch that correctly solves the puzzle. Some  
also start from a finished puzzle and move backwards logically to  
create a starting set.

Alpha Chen