2020, tracking

1 files changed, 22 insertions, 0 deletions

diff --git a/2020/day2/pwcountcheck.pl b/2020/day2/pwcountcheck.pl
new file mode 100644
index 0000000..636a5d0
--- /dev/null
+++ b/2020/day2/pwcountcheck.pl
@@ -0,0 +1,22 @@
+use strict;
+use warnings;
+
+open my $fh, '<', "input" or die "no input present, $!";
+
+my $valid = 0;
+
+while (my $line = <$fh>) {
+    chomp $line;
+    if ($line =~ m/(?'first'\d+)-(?'second'\d+) (?'char'\w): (?'rest'\w+)/) {
+
+        my $first = $+{first};
+        my $second = $+{second};
+
+        # https://www.effectiveperlprogramming.com/2010/12/count-the-number-of-things-in-a-string/
+        my $count = () = $+{rest} =~ /$+{char}/g;
+
+        $valid++ if $count >= $first and $count <= $second;
+    }
+}
+
+print("$valid");