Day 23: strongly connected graph components

#!/usr/bin/perl -w

use v5.40;

my %conn;

while (<>) {

	my ($x, $y) = /\w+/g;

	$conn{$x}{$y}++;

	$conn{$y}{$x}++;

}

my $count;

for my $x (keys %conn) {

	for my $y (keys $conn{$x}->%*) {

		for my $z (keys $conn{$x}->%*) {

			next if $z eq $y;

			next if !$conn{$z}{$y};

			$count++ if $x =~ /^t/ || $y =~ /^t/ || $z =~ /^t/;

		}

	}

}

say $count / 6;

#!/usr/bin/perl -w

use v5.40;

my %conn;

while (<>) {

	my ($x, $y) = /\w+/g;

	$conn{$x}{$y}++;

	$conn{$y}{$x}++;

}

sub walk {

	my ($set, @todo) = @_;

	my @max = @$set;

	X:

	while (my $x = shift @todo) {

		for my $y (@$set) {

			next X if !$conn{$x}{$y};

		}

		my @nset = walk([ @$set, $x ], @todo);

		@max = @nset

			if @nset > @max;

	}

	return @max;

}

say join(',', walk([], sort keys %conn));