From: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Date: Sat, 9 Dec 2023 05:27:27 +0000 (+0100)
Subject: Day 9: interesting task
X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=aoc.git;a=commitdiff_plain;h=c5060bdbc898139cea04423a11650446d3a291a3

Day 9: interesting task
---

diff --git a/2023/17.pl b/2023/17.pl
new file mode 100755
index 0000000..ab77a83
--- /dev/null
+++ b/2023/17.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/perl -w
+
+use v5.38;
+use List::Util qw(sum);
+
+my $sum;
+while (<>) {
+	my @seq = /-?\d+/g;
+	my @rest;
+	while (grep $_, @seq) {
+		for my $i (0 .. $#seq-1) {
+			$seq[$i] = $seq[$i+1]-$seq[$i];
+		}
+		push @rest, pop @seq;
+	}
+	$sum += sum @rest;
+}
+
+say $sum;
+
diff --git a/2023/18.pl b/2023/18.pl
new file mode 100755
index 0000000..f41b7b1
--- /dev/null
+++ b/2023/18.pl
@@ -0,0 +1,24 @@
+#!/usr/bin/perl -w
+
+use v5.38;
+
+my $sum;
+while (<>) {
+	my @seq = /-?\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;
+	}
+	my $s = 0;
+	for (reverse @rest) {
+		$s = $_ - $s;
+	}
+	$sum += $s;
+}
+
+say $sum;
+