Sudoku Py / C++11 / D?

[Era Scarecrow]

On Tuesday, 21 August 2012 at 15:55:08 UTC, maarten van damme 
wrote:
> Thank you very much, this makes everything more clearer. I'm 
> not very familiar with binary operators so the comments help 
> out a lot. Would you mind it if I shamelessly copy your 
> solution of using shorts to store possibilities in?

  Binary operators are fun :) Once you get the hang of it you know 
exactly what you're doing. Think of AND = Keep only, OR = Set, 
Xor = switch state. so.

  AND &
  source  0 0 1 1
  data    0 1 0 1
  result  0 0 0 1

  OR |
  source  0 0 1 1
  data    0 1 0 1
  result  0 1 1 1

  Xor ^
  source  0 0 1 1
  data    0 1 0 1
  result  0 1 1 0

>> Was that sarcasm? My own code only uses copying when it's 
>> working in the next section of brute force, otherwise it's all 
>> referenced.

> No, that wasn't sarastic. If you look at my last code you see 
> that I "compose" the squares using something like [....] ~ 
> [.....] ~ [.....] Using a foreach loop and copying the values 
> was 10 times faster...

  Curious. With fixed array sizes it should do a bulk memory copy, 
unless you are going from static/fixed to dynamic. Also curious 
is in my code it allowed me to do a forced struct copy (move?) 
when I found a success and just copied the result to the current 
structure. I'll post my two revisions up later.

>> I only use exceptions twice and both when it would be unable 
>> to find a solution; I suppose I can try putting nothrow on 
>> everything and return a bool if it had an error for solving, 
>> or when it had to, inside a structure. Mmmm... I'll give it a 
>> try.

> Yes but when your solver reaches a solution that is wrong, you 
> get a whole "branch" of numbers falling of, all throwing a 
> "broken sudoku" exception. It will rarely be called once.

  True. I already tried removing it, and curiously enough the code 
performs 10x-200x faster. Except all my debugging statements now 
fail since they aren't nothrow :P

>> Not normal but it can be arranged. :p
>
> But I used it in my getRegion code where I do simple 
> calculations on the contents of that array. It is slower 
> there...