Sudoku Py / C++11 / D?

[Era Scarecrow]

On Monday, 20 August 2012 at 00:13:41 UTC, maarten van damme 
wrote:
> I'm using a static array.

  Good good..

> I'm hesitating though if I should store possibilities in a 
> precalculated array or calculate them in-place. If I 
> precalculate the possibilities I'd have to copy them over and 
> over so I don't know if it's smart.

  Depends. Do you plan on doing more than brute force? Having it 
bulk copy them may not be that bad if it's all in one place, and 
if you do it like that you have all the combinations that carry 
forward to the next level and if you back out it undoes them all 
automatically.

  In my updated code it gets it done in about 5 seconds compared 
to 12. To get it even faster I would have to implement a third 
algorithm to help reduce possibilities, the stored results then 
become a must compared to on-the-fly.

> Going even further I could even store a filled-in value as an 
> array with one possibilities...

  As long as you can tell it apart for it to work, that's up to 
you.