adventofcode/2023/08/Part1.pm

use 5.38.0;

package Part1;

use List::AllUtils qw/ /;

sub parse_input ($input) {
    my ( $directions, undef, @nodes ) = split "\n", $input;

    $directions = [ split "", $directions =~ s/R/1/gr =~ s/L/0/gr ];

    my %nodes;

    for (@nodes) {
        my @n = /([A-Z\d]+)/g;
        $nodes{ shift @n } = \@n;
    }

    return {
        directions => $directions,
        nodes      => \%nodes
    };
}

sub solution_1 ($input) {
    my $p          = parse_input($input);
    my @directions = $p->{directions}->@*;
    my %nodes      = $p->{nodes}->%*;

    my $visited    = 0;
    my $next_index = 0;
    my $current    = 'AAA';

    while ( $current ne 'ZZZ' ) {
        $visited++;

        $current =
          $nodes{$current}->[ $directions[ $next_index++ % @directions ] ];
    }

    return $visited;

}

1;