From 3d747e3a9be7b690c4ef856f18a8aad7b8bfb33c Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Tue, 9 Dec 2025 08:16:38 +0100
Subject: [PATCH] Day 09: wrong assumptions

---
 2025/17.pl | 15 +++++++++++++++
 2025/18.pl | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100755 2025/17.pl
 create mode 100755 2025/18.pl

diff --git a/2025/17.pl b/2025/17.pl
new file mode 100755
index 0000000..ec27037
--- /dev/null
+++ b/2025/17.pl
@@ -0,0 +1,15 @@
+#!/usr/bin/perl -w
+
+use v5.42;
+
+my @coords = map { [ /\d+/g ] } <>;
+
+my $max;
+for my $i (0 .. $#coords-1) {
+	for my $j ($i+1 .. $#coords) {
+		my $area = (1+abs($coords[$i][0]-$coords[$j][0]))
+			* (1+abs($coords[$i][1]-$coords[$j][1]));
+		$max = $area if !defined $max || $area > $max;
+	}
+}
+say $max;
diff --git a/2025/18.pl b/2025/18.pl
new file mode 100755
index 0000000..c0a1e2f
--- /dev/null
+++ b/2025/18.pl
@@ -0,0 +1,47 @@
+#!/usr/bin/perl -w
+
+use v5.42;
+use List::Util qw(max min);
+
+my @coords = map { [ /\d+/g ] } <>;
+my @lines;
+for my $i (0 .. $#coords) {
+	my $j = $i+1;
+	$j = 0 if $j > $#coords;
+	push @lines, [ @{ $coords[$i] }, @{ $coords[$j] } ];
+}
+
+my $max;
+for my $i (0 .. $#coords-1) {
+	RECT:
+	for my $j ($i+1 .. $#coords) {
+		my ($x0, $y0, $x1, $y1) = (
+			min ($coords[$i][0], $coords[$j][0]),
+			min ($coords[$i][1], $coords[$j][1]),
+			max ($coords[$i][0], $coords[$j][0]),
+			max ($coords[$i][1], $coords[$j][1]),
+		);
+		for my $k (0 .. $#coords) {
+			next if $k == $i || $k == $j;
+			my ($xk, $yk) = @{ $coords[$k] };
+			next RECT if $xk > $x0 && $xk < $x1
+				&& $yk > $y0 && $yk < $y1;
+		}
+		for my $k (0 .. $#lines) {
+			my ($lx0, $ly0, $lx1, $ly1) = @{ $lines[$k] };
+			($lx0, $lx1) = ($lx1, $lx0) if $lx1 < $lx0;
+			($ly0, $ly1) = ($ly1, $ly0) if $ly1 < $ly0;
+			if ($lx0 == $lx1) {
+				next if $lx0 <= $x0 || $lx0 >= $x1;
+				next RECT if $ly0 <= $y0 && $ly1 >= $y1;
+			} else {
+				next if $ly0 <= $y0 || $ly0 >= $y1;
+				next RECT if $lx0 <= $x0 && $lx1 >= $x1;
+			}
+		}
+		my $area = (1+abs($coords[$i][0]-$coords[$j][0]))
+			* (1+abs($coords[$i][1]-$coords[$j][1]));
+		$max = $area if !defined $max || $area > $max;
+	}
+}
+say $max;
-- 
2.47.3