3 x speed up by moving IF

1 files changed, 8 insertions, 8 deletions

diff --git a/challenge-118/james-smith/perl/ch-2.pl b/challenge-118/james-smith/perl/ch-2.pl
index 4045d50ac0..a9d91e32f4 100644
--- a/challenge-118/james-smith/perl/ch-2.pl
+++ b/challenge-118/james-smith/perl/ch-2.pl
@@ -10,8 +10,8 @@ use Data::Dumper qw(Dumper);
 
 my @dir = ([-2,1],[2,1],[-2,-1],[2,-1],[-1,2],[1,2],[-1,-2],[1,-2]);
 
-my( $SIZE, @treasures ) = ( 8, qw(a2 b1 b2 b3 c4 e6) );
-my( $sol, $best_len, $best_rt ) = ( 0, $SIZE*$SIZE + 1 );
+my @treasures = qw(a2 b1 b2 b3 c4 e6);
+my( $sol, $best_len, $best_rt ) = ( 0, 65 );
 $sol |= 1 <<  8 * (substr $_,1) - 105 + ord $_ foreach @treasures;
 
 ## We convert the "letter/digit" co-ordinates into a square number
@@ -31,29 +31,29 @@ $sol |= 1 <<  8 * (substr $_,1) - 105 + ord $_ foreach @treasures;
 ## to bytes using chr/ord.
 
 
-walk( 0, $SIZE-1, 0, '' );   ## Walk the tree starting from top-left
+walk( 0, 7, 0, q() );   ## Walk the tree starting from top-left
 
-say length $best_rt, ' - ', show_rt( $best_rt );     ## Show best rt
+say length $best_rt, q( - ), show_rt( $best_rt ); ## Show best route
 
 sub walk {
   my( $x, $y, $seen, $rt ) = @_;
   ## Skip if the new "chain" will be bigger than the best chain so far
   ## If we have fallen off the sides of the board
   ## Or if we have already visited the square.
-  return if $best_len <= length $rt
-         || $x < 0 || $y < 0 || $x >= $SIZE || $y >= $SIZE
-         || $seen & ( my $v = 1 << (my $t = 8*$y + $x ) );
+  return if $x < 0 || $y < 0 || $x > 7 || $y > 7
+         || $seen & ( my $v = 1 << ( my $t = 8*$y + $x ) );
   $seen |= $v;
   $rt   .= chr $t;
   return ($best_rt,$best_len) = ($rt,-1+length $rt)
     if ($seen & $sol) == $sol;
+  return if $best_len <= length $rt;
   walk( $x + $_->[0], $y + $_->[1], $seen, $rt ) foreach @dir;
 }
 
 sub show_rt {
   my %t = map { $_ => 1 } @treasures;
   return join q(),
-          map { sprintf ' %s%s', exists$t{$_}?'*':' ', $_ }
+          map { sprintf ' %s%s', exists$t{$_}?q(*):q( ), $_ }
           map { chr( ($_&7) + 97 ).(1 + ($_>>3)) }
           map { ord $_ }
         split m{}, shift;