2020, tracking

1 files changed, 19 insertions, 0 deletions

diff --git a/2020/day2/pwindexcheck.pl b/2020/day2/pwindexcheck.pl
new file mode 100644
index 0000000..69a26b5
--- /dev/null
+++ b/2020/day2/pwindexcheck.pl
@@ -0,0 +1,19 @@
+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/(?<idx_1>\d+)-(?<idx_2>\d+) (?<char>\w): (?<rest>\w+)/) {
+
+        my $first = substr( $+{rest}, $+{idx_1} - 1 , 1 );
+        my $second = substr( $+{rest}, $+{idx_2} - 1 , 1 );
+
+        $valid++ if $first eq $+{char} xor $second eq $+{char};
+    }
+}
+
+print("$valid");