From: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Date: Fri, 13 Dec 2024 12:09:40 +0000 (+0100)
Subject: Day 13: linear equations
X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=commitdiff_plain;h=a86def06881eee1c93b637479cf4f5378ea090a5;p=aoc.git

Day 13: linear equations
---

diff --git a/2024/25.pl b/2024/25.pl
new file mode 100755
index 0000000..be0ca50
--- /dev/null
+++ b/2024/25.pl
@@ -0,0 +1,25 @@
+#!/usr/bin/perl -w
+
+use v5.40;
+
+my $cost;
+while (1) {
+	my ($ax, $ay) = <> =~/\d+/g;
+	my ($bx, $by) = <> =~/\d+/g;
+	my ($px, $py) = <> =~/\d+/g;
+
+	for my $na (1 .. 100) {
+		last if $ax * $na > $px;
+		last if $ay * $na > $py;
+		next if ($px - $ax * $na) % $bx;
+		next if ($py - $ay * $na) % $by;
+		next if ($px - $ax * $na) / $bx != ($py - $ay * $na) / $by;
+		my $c = $na*3 + ($px - $ax * $na) / $bx;
+		$cost += $c;
+
+		last;
+	}
+	last if !defined <>;
+}
+
+say $cost;
diff --git a/2024/26.pl b/2024/26.pl
new file mode 100755
index 0000000..4b6b4a3
--- /dev/null
+++ b/2024/26.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/perl -w
+
+use v5.40;
+
+my $cost;
+while (1) {
+	my ($ax, $ay) = <> =~/\d+/g;
+	my ($bx, $by) = <> =~/\d+/g;
+	my ($px, $py) = <> =~/\d+/g;
+	$px += 10000000000000;
+	$py += 10000000000000;
+
+	my $nb = ($px*$ay - $py*$ax) / ($bx*$ay - $ax*$by);
+	my $na = ($px - $nb*$bx) / $ax;
+
+	$cost += 3*$na+$nb
+		if $na == int($na) && $nb == int($nb);
+
+	last if !defined <>;
+}
+say $cost;