From 16f4451d576062f31a2858fa15d1e09150faa04d Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Mon, 8 Dec 2025 07:00:21 +0100
Subject: [PATCH] Day 08: DFS and Dijkstra

---
 2025/15.pl | 40 ++++++++++++++++++++++++++++++++++++++++
 2025/16.pl | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)
 create mode 100755 2025/15.pl
 create mode 100755 2025/16.pl

diff --git a/2025/15.pl b/2025/15.pl
new file mode 100755
index 0000000..913357d
--- /dev/null
+++ b/2025/15.pl
@@ -0,0 +1,40 @@
+#!/usr/bin/perl -w
+
+use v5.42;
+use experimental 'multidimensional';
+use List::Util qw(sum);
+
+my @boxes = map { [ /\d+/g ] } <>;
+
+my %dists;
+for my $i (0 .. $#boxes-1) {
+	for my $j ($i+1 .. $#boxes) {
+		$dists{$i,$j} = sqrt(sum map {
+			($boxes[$i][$_] - $boxes[$j][$_])**2 } 0 .. 2);
+	}
+}
+
+my @mind = sort { $dists{$a} <=> $dists{$b} } keys %dists;
+my %d1k = map { $_ => $dists{$_} } splice(@mind, 0, 1000);
+my %neighs;
+for my $node (keys %d1k) {
+	my ($n1, $n2) = split /$;/, $node;
+	push @{ $neighs{$n1} }, $n2;
+	push @{ $neighs{$n2} }, $n1;
+}
+
+my %comps;
+my %seen;
+sub walk($node, $state = undef) {
+	return if $seen{$node}++;
+	$state //= $node;
+	$comps{$state}++;
+	for my $n (@{ $neighs{$node} }) {
+		walk($n, $state);	
+	}
+}
+
+walk($_) for keys %neighs;
+my @v = reverse sort { $a <=> $b } values %comps;
+
+say $v[0]*$v[1]*$v[2];
diff --git a/2025/16.pl b/2025/16.pl
new file mode 100755
index 0000000..137a0a4
--- /dev/null
+++ b/2025/16.pl
@@ -0,0 +1,45 @@
+#!/usr/bin/perl -w
+
+use v5.42;
+use experimental 'multidimensional';
+use List::Util qw(sum);
+
+$; = ';';
+
+my @boxes = map { [ /\d+/g ] } <>;
+
+my %dists;
+for my $i (0 .. $#boxes-1) {
+	for my $j ($i+1 .. $#boxes) {
+		$dists{$i,$j} = sqrt(sum map {
+			($boxes[$i][$_] - $boxes[$j][$_])**2
+		} 0 .. 2);
+	}
+}
+
+my %seen;
+my $comps;
+
+for my $v (sort { $dists{$a} <=> $dists{$b} } keys %dists) {
+	my ($n1, $n2) = split /$;/, $v;
+	my $st = $seen{$n1};
+	if (!defined $st) {
+		$st = $seen{$n1} = $n1;
+		$comps++;
+	}
+	if (defined $seen{$n2} && $seen{$n2} != $st) {
+		my $prev = $seen{$n2};
+		for my $i (0 .. $#boxes) {
+			$seen{$i} = $st if defined $seen{$i} && $seen{$i} == $prev;
+		}
+		$comps--;
+	} else {
+		$seen{$n2} = $st;
+	}
+
+	if (keys %seen == @boxes && $comps == 1) {
+		say $boxes[$n1][0] * $boxes[$n2][0];
+		last;
+	}
+}
+
-- 
2.47.3