X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=blobdiff_plain;f=2023%2F18.pl;h=43be85e53e58467c8948857210ba38313fa53991;hb=0e9a2132dee3b812571f5506794af300aa1d1d15;hp=f41b7b1ed52f85f599398fa708eb45ca46b625d1;hpb=c5060bdbc898139cea04423a11650446d3a291a3;p=aoc.git

diff --git a/2023/18.pl b/2023/18.pl
index f41b7b1..43be85e 100755
--- a/2023/18.pl
+++ b/2023/18.pl
@@ -4,20 +4,11 @@ use v5.38;
 
 my $sum;
 while (<>) {
-	my @seq = /-?\d+/g;
-	my @rest;
+	my @seq = reverse /-?\d+/g;
 	while (grep $_, @seq) {
-		push @rest, $seq[0];
-		for my $i (0 .. $#seq-1) {
-			$seq[$i] = $seq[$i+1]-$seq[$i];
-		}
-		pop @seq;
+		$seq[$_] = $seq[$_+1]-$seq[$_] for 0 .. $#seq-1;
+		$sum += pop @seq;
 	}
-	my $s = 0;
-	for (reverse @rest) {
-		$s = $_ - $s;
-	}
-	$sum += $s;
 }
 
 say $sum;