aoc2021

Advent of Code 2021 solutions in Perl.
git clone git://git.samirparikh.com/aoc2021
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day02.pl (951B) - raw

      1 #!/usr/bin/env perl
      2 
      3 use strict;
      4 use warnings;
      5 use v5.22;
      6 
      7 if (@ARGV !=1) {
      8     die "Usage: $0 [input-filename]";
      9 }
     10 
     11 my $input_filename = $ARGV[0];
     12 open my $filehandle, '<', $input_filename or
     13     die "Could not open input file $input_filename: $!";
     14 
     15 chomp( my @input = ( <$filehandle> ) );
     16 
     17 # Part 1
     18 my ($horizontal, $depth);
     19 
     20 foreach (@input) {
     21     my ($direction, $distance) = split;
     22     $horizontal += $distance if ($direction eq 'forward');
     23     $depth      += $distance if ($direction eq 'down');
     24     $depth      -= $distance if ($direction eq 'up');
     25 }
     26 
     27 say $horizontal * $depth;
     28 
     29 # Part 2
     30 ($horizontal, $depth) = (0, 0);
     31 my $aim = 0;
     32 
     33 foreach (@input) {
     34     my ($direction, $distance) = split;
     35     if ($direction eq 'forward') {
     36         $horizontal += $distance;
     37         $depth      += $aim * $distance;
     38     }
     39     $aim      += $distance if ($direction eq 'down');
     40     $aim      -= $distance if ($direction eq 'up');
     41 }
     42 
     43 say $horizontal * $depth;