aoc2021

commit 7fe940345556c6727443df409e20d4005e7fb322
parent 9f929507996da7d9f63427f9f5f2c4a0cb213d54
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Thu,  2 Dec 2021 14:09:35 +0000

add Day 02 solutions

Diffstat:
A
day02.pl
 | 
43
+++++++++++++++++++++++++++++++++++++++++++

1 file changed, 43 insertions(+), 0 deletions(-)
diff --git a/day02.pl b/day02.pl
@@ -0,0 +1,43 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use v5.22;
+
+if (@ARGV !=1) {
+    die "Usage: $0 [input-filename]";
+}
+
+my $input_filename = $ARGV[0];
+open my $filehandle, '<', $input_filename or
+    die "Could not open input file $input_filename: $!";
+
+chomp( my @input = ( <$filehandle> ) );
+
+# Part 1
+my ($horizontal, $depth);
+
+foreach (@input) {
+    my ($direction, $distance) = split;
+    $horizontal += $distance if ($direction eq 'forward');
+    $depth      += $distance if ($direction eq 'down');
+    $depth      -= $distance if ($direction eq 'up');
+}
+
+say $horizontal * $depth;
+
+# Part 2
+($horizontal, $depth) = (0, 0);
+my $aim = 0;
+
+foreach (@input) {
+    my ($direction, $distance) = split;
+    if ($direction eq 'forward') {
+        $horizontal += $distance;
+        $depth      += $aim * $distance;
+    }
+    $aim      += $distance if ($direction eq 'down');
+    $aim      -= $distance if ($direction eq 'up');
+}
+
+say $horizontal * $depth;