From 273fff2812d97c808dd7dca0560aa5aceab3b632 Mon Sep 17 00:00:00 2001
From: June McEnroe <june@causal.agency>
Date: Fri, 3 Dec 2021 09:41:42 -0500
Subject: Solve day 3 part 1

---
 2021/day03.pl | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 2021/day03.pl

(limited to '2021/day03.pl')

diff --git a/2021/day03.pl b/2021/day03.pl
new file mode 100644
index 0000000..8a62021
--- /dev/null
+++ b/2021/day03.pl
@@ -0,0 +1,17 @@
+use strict;
+use warnings;
+my @nums;
+while (<>) {
+	chomp;
+	push @nums, oct("0b".$_);
+}
+my $gamma = 0;
+for (my $i = 0; $i < 12; $i++) {
+	my $ones = 0;
+	foreach (@nums) {
+		$ones++ if $_ & (1 << $i);
+	}
+	$gamma |= 1 << $i if $ones > @nums / 2;
+}
+my $epsilon = ~$gamma & 0xFFF;
+print $gamma * $epsilon, "\n";
-- 
cgit 1.4.1