constraint based killer sudoku solver performance improvements

Blockheads Oi Oi breamoreboy at
Fri Jan 27 02:47:35 EST 2012

On 27/01/2012 06:57, Frank Millman wrote:
> "Blockheads Oi Oi"<breamoreboy at>  wrote:
>> I have a working program based on [1] that sets up all different
>> constraints for each row, column and box and then sets exact sum
>> constraints for each cage.  It'll run in around 0.2 secs for a simple
>> problem, but a tough one takes 2 hours 45 minutes.  I did some research
>> into improving the performance and found [2] but can't work out how to
>> implement the constraints given.  Can someone please help, assuming that
>> it's even possible.
>> [1]
>> [2]
> I don't have an answer, but are you aware of this -
> It is a sudoko solver written in pure python.
> I don't know what you call a tough problem, but this one solves the hardest
> one I have thrown at it in the blink of an eye. It also outputs a full trace
> of  the reasoning it used to arrive at a solution.
> Frank Millman

I'd looked at this years back and forgotten all about it so thanks for 
the reminder :)  Some of the code names directly match ideas given in my 
[2] above so I'll take another look.

Mark Lawrence.

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