From: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Date: Mon, 25 Dec 2023 06:59:04 +0000 (+0100)
Subject: Day 25: examining the input
X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=commitdiff_plain;h=4de6ee01c72c92a6b761d5652ae249981680ed77;p=aoc.git

Day 25: examining the input
---

diff --git a/2023/49.pl b/2023/49.pl
new file mode 100755
index 0000000..5c11b3e
--- /dev/null
+++ b/2023/49.pl
@@ -0,0 +1,71 @@
+#!/usr/bin/perl -w
+
+use v5.38;
+use experimental 'for_list';
+
+=for comment
+
+convert the input to .dot format:
+
+strict graph g {
+ggk -- { tkd };
+vcd -- { nhn };
+xhj -- { mft rtg hvp sgl };
+hgx -- { dxq stc cfn };
+...
+}
+
+Then run
+
+neato -Tsvg 49in.dot
+
+and find the components and their edges.
+
+=cut
+
+my %g;
+while (<>) {
+	my ($n1, @ns) = /\w+/g;
+	for my $n (@ns) {
+		$g{$n}{$n1} = 1;
+		$g{$n1}{$n} = 1;
+	}
+}
+
+sub walk {
+	my ($node, $seen) = @_;
+	my @q = $node;
+	my $visited;
+	while (@q) {
+		my ($n, $d) = shift @q;
+		next if $seen->{$n}++;
+		$visited++;
+		for my $n1 (keys %{ $g{$n} }) {
+			push @q, $n1;
+		}
+	}
+	return $visited;
+}
+
+sub comps {
+	my %seen;
+	my $m = 1;
+	my $comps;
+	while (%seen != keys %g) {
+		my $prev = 0;
+		for my $n (keys %g) {
+			next if $seen{$n};
+			$m *= walk($n, \%seen);
+			$comps++;
+		}
+	}
+	say "$comps mul=$m" if $comps > 1;
+	return $comps;
+}
+
+for my ($n1, $n2) (qw(rrz pzq jtr mtq ddj znv)) {
+	delete $g{$n1}{$n2};
+	delete $g{$n2}{$n1};
+}
+
+comps();