#!/usr/local/bin/perl
# day 2022-05
# taken from 
# https://github.com/Abigail/AdventOfCode2022/blob/master/Day_05/solution.pl
use strict;
use warnings;
use v5.32;
use Data::Dumper;

@ARGV = "input" unless @ARGV;

my @stacks1;
my @stacks2;
while ( <> ) {
    last if m/^ 1/;
    my $stack_number = 1;
    while ( m/(?:   |\[([A-Z])\]) ?/g ) {
        # crates at the top of the stack will be at the end of the array
        # (e.g. lower crates will be at the beginning of the array)
        unshift @{ $stacks1[ $stack_number ] } => $1 if $1;
        unshift @{ $stacks2[ $stack_number ] } => $1 if $1;
        $stack_number++;
    }
}

<>; # read blank line

while (<>) {
    my ( $move, $from, $to ) = m/\d+/g;
    foreach ( 1 .. $move ) {
        push @{ $stacks1[ $to ] } => pop @{ $stacks1[ $from ] };
    }
}


my $part1 = '';
$part1 .= $_->[-1] foreach @stacks1[ 1 .. $#stacks1];

say "part 1: ", $part1;