first few days

2/1.pl

@@ -0,0 +1,35 @@
+#!/usr/bin/perl
+
+use strict;
+
+chomp (my @data = <STDIN>);
+
+my ($ck2, $ck3);
+foreach my $w (@data) {
+	my ($r2, $r3) = checksum($w);
+	#print "$r2, $r3\n";
+	$ck2 += $r2;
+	$ck3 += $r3;
+}
+print $ck2 * $ck3 . "\n";
+
+
+sub checksum {
+	my $word = shift;
+	
+	my %seen;
+	foreach my $letter (split //, $word) {
+		$seen{$letter}++
+	}
+
+	my $twos = 0;
+	my $threes = 0;
+	foreach my $k (keys %seen) {
+		# print "$k $seen{$k}\n";
+		$twos=1 if ($seen{$k} == 2);
+		$threes=1 if ($seen{$k} == 3);
+	}
+
+	return ($twos, $threes);
+
+}