From 81d7b11934be0f57efd2021793730ebe6f522ac2 Mon Sep 17 00:00:00 2001
From: June McEnroe <june@causal.agency>
Date: Fri, 3 Dec 2021 10:57:38 -0500
Subject: Refactor day 3 using grep to count ones

C has turned my brain to for-loop goop.
---
 2021/day03.pl | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

(limited to '2021')

diff --git a/2021/day03.pl b/2021/day03.pl
index 7e8d2fc..cd8b1db 100644
--- a/2021/day03.pl
+++ b/2021/day03.pl
@@ -6,31 +6,27 @@ while (<>) {
 	$bits = length($_);
 	push @nums, oct("0b".$_);
 }
-sub countOnes {
+sub moreOnes {
 	my $i = shift;
-	my $ones = 0;
-	foreach (@_) {
-		$ones++ if $_ & (1 << $i);
-	}
-	$ones;
+	(grep { $_ & (1 << $i) } @_) >= @_ / 2;
 }
 my $gamma = 0;
 for (my $i = 0; $i < $bits; $i++) {
-	$gamma |= 1 << $i if countOnes($i, @nums) > @nums / 2;
+	$gamma |= 1 << $i if moreOnes($i, @nums);
 }
 my $epsilon = ~$gamma & ((1 << $bits) - 1);
 print $gamma * $epsilon, "\n";
 my @o2 = @nums;
 my $i = $bits - 1;
 while (@o2 > 1) {
-	my $most = (countOnes($i, @o2) >= @o2 / 2) << $i;
+	my $most = moreOnes($i, @o2) << $i;
 	@o2 = grep { ($_ & (1 << $i)) == $most } @o2;
 	$i--;
 }
 my @co2 = @nums;
 $i = $bits - 1;
 while (@co2 > 1) {
-	my $least = !(countOnes($i, @co2) >= @co2 / 2) << $i;
+	my $least = !moreOnes($i, @co2) << $i;
 	@co2 = grep { ($_ & (1 << $i)) == $least } @co2;
 	$i--;
 }
-- 
cgit 1.4.1