X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=blobdiff_plain;f=2023%2F18.pl;h=1ea75534d67e350795caff93b03a51897714a5ed;hb=4eaa410b226684b5ff5430fc4cef481f7083a36b;hp=f41b7b1ed52f85f599398fa708eb45ca46b625d1;hpb=c5060bdbc898139cea04423a11650446d3a291a3;p=aoc.git

diff --git a/2023/18.pl b/2023/18.pl
index f41b7b1..1ea7553 100755
--- a/2023/18.pl
+++ b/2023/18.pl
@@ -1,23 +1,19 @@
 #!/usr/bin/perl -w
 
 use v5.38;
+use List::Util qw(sum);
 
 my $sum;
 while (<>) {
-	my @seq = /-?\d+/g;
+	my @seq = reverse /-?\d+/g;
 	my @rest;
 	while (grep $_, @seq) {
-		push @rest, $seq[0];
 		for my $i (0 .. $#seq-1) {
 			$seq[$i] = $seq[$i+1]-$seq[$i];
 		}
-		pop @seq;
+		push @rest, pop @seq;
 	}
-	my $s = 0;
-	for (reverse @rest) {
-		$s = $_ - $s;
-	}
-	$sum += $s;
+	$sum += sum @rest;
 }
 
 say $sum;