reg.ru sponsors of YAPC::EU::2013 set this challenge based on the game of Go:

1. Problems are given for a Go training board with the size of 9×9.
2. Black moves first.
3. There are no stones already captured on the board.

Input: nine lines which represent the playing board are sent to STDIN. Lines consist of spaces (for vacant points on the board), "w" symbols (for white stones) and "b" symbols (black stones) and end with the new line symbol ("\n").

Output: сoordinates (row and column numbers separated with a space, counted from one) of points, a move to which results in the capture of white stones. Results must be sent to STDOUT, one point per line. Results must contain all the possible moves on the board which would lead to the capture of white stones. Points are to be output in the order of their position on the board (left to right, top to bottom).

This is my first attempt at Perl-golf and (because BooK wasn't here this year) I actually won with 205 characters. (Woo hoo!)

#!perl
$b=++$/x11 .<>;for$i(9..99){if(($x=$b)=~s/^(.{$i}) /$1x/s){while($x=~/
+w/g){$_="$`W$'";1while
s/w((?<=W.{10})|(?<=W.)|(?=.{9}W|W))/W/s;/W((?<= .{10})|(?<= .)|(?=.{9
+} | ))/s||$i=~/./+(print"$& $'\n")+last}}}
[download]

Or with comments and whitespace

#!perl
$b = ++$/ x 11 . <>;                               # $/='1' (not prese
+nt in input). Slurp STDIN.
                                                   # Prepend '11111111
+111' so top left is at 11.
                                                   # Leave the "\n" in
+ to act as border and make
                                                   # rows 10 so linear
+ pos is also row/col.
for $i (9..99) {                                   # Scan all possible
+ cells (including border).
  if( ($x=$b) =~ s/^(.{$i}) /$1x/s ) {             # If cell is ' ' pl
+ace 'x' in a copy of board.
    while( $x=~/w/g ) {                            # Consider each 'w'
+ in turn and
      $_ = "$`W$'";                                #   copy board high
+ighing that 'w' as 'W'.
      1 while                                      # Until you run out
+,
        s/w((?<=W.{10})|(?<=W.)|(?=.{9}W|W))/W/s;  #   highlight a nei
+ghbouring 'w'.
      /W((?<= .{10})|(?<= .)|(?=.{9} | ))/s        # Find a 'W' neighb
+ouring a ' '.
       ||                                          # If there is no su
+ch peg we have captured.
          $i=~/./ +                                # Split row number 
+out of cell number.
          (print"$& $'\n") +                       # Print row and col
+unm.
          last                                     # Advance to next p
+ossible cell.  
    }
  }
}
[download]

Improvements from the Monks welcome.

---

---

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! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

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:
	&		&
	<		&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.