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copied!<h2>Perl, <strike>166</strike> 160 characters</h2> <p>Perl, <strike>251</strike> <strike>248</strike> <strike>246</strike> <strike>222</strike> <strike>214</strike> <strike>208</strike> <strike>203</strike> <strike>201</strike> <strike>193</strike> <strike>190</strike> <strike>180</strike> <strike>176</strike> <strike>173</strike> <strike>170</strike> 166 --> 160 chars. </p> <p>Solution had 166 strokes when this contest ended, but A. Rex has found a couple ways to shave off 6 more characters:</p> <pre><code>s!.!$t{$s++}=$&!ge,$s=$r+=99for<>;%d='>.^1<2v3'=~/./g;($r)=grep$d|=$d{$t{$_}},%t; {$_=$t{$r+=(1,-99,-1,99)[$d^=3*/\\/+m</>]};/[\/\\ ]/&&redo}die/x/?true:false,$/ </code></pre> <p>The first line loads the input into <code>%t</code>, a table of the board where <code>$t{99*i+j}</code> holds the character at row <em>i</em>,column <em>j</em>. Then,</p> <pre><code>%d=split//,'>.^1<2v3' ; ($r)=grep{$d|=$d{$t{$_}}}%t </code></pre> <p>it searches the elements of <code>%t</code> for a character that matches <code>> ^ <</code> or <code>v</code>, and simultaneously sets <code>$d</code> to a value between 0 and 3 that indicates the initial direction of the laser beam.</p> <p>At the beginning of each iteration in the main loop, we update <code>$d</code> if the beam is currently on a mirror. XOR'ing by 3 gives the correct behavior for a <code>\</code> mirror and XOR'ing by 1 gives the correct behavior for a <code>/</code> mirror.</p> <pre><code>$d^=3*/\\/+m</> </code></pre> <p>Next, the current position <code>$r</code> is updated accoring to the current direction.</p> <pre><code>$r+=(1,-99,-1,99)[$d] ; $_ = $t{$r} </code></pre> <p>We assign the character at the current position to <code>$_</code> to make convenient use of the match operators.</p> <pre><code>/[\/\\ ]/ && redo </code></pre> <p>Continue if we are on a blank space or a mirror character. Otherwise we terminate <code>true</code> if we are on the target (<code>$_ =~ /x/</code>) and <code>false</code> otherwise.</p> <p>Limitation: may not work on problems with more than 99 columns. This limitation could be removed at the expense of 3 more characters,</p>

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