The question is where you want to draw the line between finding the solution and providing information about the solution. Based on the encoding of the states of the world used in the code above (represented by $s), the expression

grep!$s{$_}&!($s&8&&~$s&$_&7)&!(~$s&8&&$s&~$_&7)&&($z=$s^$_)&8&&(($z&= +7)<3|$z==4),15,grep$_%3,1..14

is used to find the next possible moves based on the rules given. It constructs the following implicit tree:

0-8 11-1 7-15 \ / \ / 10-2 13-5 \ / 14-4

Already, I have excluded states 3, 6, 9 and 12 as in thoses states something gets eaten. Looking at this tree, the problem is to find a path from "0" to "15" which is rather simple.

The question is how much of this information is allowed to be input to the script rather being calculated. In the extreme, one could just provide the two solutions and find the shortest script to print them without having to bother moving boats, wolfs, cabbages and goats. But that would be not very interesting...

And to clarify: the grep expression is not an obfuscated version of the tree but finds possible moves based upon the rules ($s is where we are, $_ a possible next state):

grep !$s{$_} # we have not been at $_ already &!($s&8 # prohibit the boat is on the right bank initia +lly &&~$s&$_&7) # and a move from left to right &!(~$s&8 # prohibit the boat is on the left bank initial +ly &&$s&~$_&7) # and a move from right to left &&($z=$s^$_)&8 # the boat moves &&(($z&=7)<3|$z==4), # with at most one passenger 15,grep$_%3,1..14 # possible choices for moves

In reply to Re^5: Golf: Cabbage, Goat, Wolf by hdb
in thread Golf: Cabbage, Goat, Wolf by educated_foo

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, 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, 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.