(Inspired by Re: Subroutine overhead in Perl)

Challenge: Golf a sudoku solver. Bonus points to fast solutions as well. Correct solutions must provide all solutions to a given starting position (test data provided below).

If you want, you can use any/all of the following infrastructure:

  1. @grid - starts with the initial position (with 0's for empty squares).
  2. %search - contains 81 entries, indexed by 0-80, each pointing to an arrayref of 21 entries. These entries are squares that cannot contain the same value as the key.
  3. sudoku_print() - a method that prints the sudoku board as listed in @grid.
  4. Assume that the input has already been parsed into @grid.

I'll post my solutions in a response to this post.

Some samples are: 

-,-,4,-,-,2,-,-,3
-,2,-,-,9,-,7,1,5
7,-,-,3,1,-,4,-,-
-,1,-,-,-,-,2,-,9
-,4,-,2,7,-,-,-,6
2,8,-,5,-,-,-,-,-
5,-,-,-,-,3,6,-,4
-,3,1,-,-,8,-,-,2
4,6,-,-,5,-,-,3,1

-,-,5,-,-,-,-,4,-
-,-,-,8,-,-,-,-,6
3,-,2,-,-,1,-,-,-
-,-,-,-,-,4,-,2,-
-,-,9,-,-,-,5,-,-
-,6,-,3,-,-,-,-,-
-,-,-,-,-,-,-,-,3
-,-,-,-,-,5,-,-,-
-,1,-,-,-,-,6,8,-

-,-,-,-,-,-,-,-,-
-,-,-,-,-,3,-,8,5
-,-,1,-,2,-,-,-,-
-,-,-,5,-,7,-,-,-
-,-,4,-,-,-,1,-,-
-,9,-,-,-,-,-,-,-
5,-,-,-,-,-,-,7,3
-,-,2,-,1,-,-,-,-
-,-,-,-,4,-,-,-,9

(This input has two solutions. Both are required to be correct.)
9,-,6,-,7,-,4,-,3
-,-,-,4,-,-,2,-,-
-,7,-,-,2,3,-,1,-
5,-,-,-,-,-,1,-,-
-,4,-,2,-,8,-,6,-
-,-,3,-,-,-,-,-,5
-,3,-,7,-,-,-,5,-
-,-,7,-,-,5,-,-,-
4,-,5,-,1,-,7,-,8

[download]
My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

In reply to Golf: Sudoku solving by dragonchild

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.