Year 2018

[aoc.git] / 2018 / 09.pl

diff --git a/2018/09.pl b/2018/09.pl
new file mode 100755 (executable)
index 0000000..7abf1d8
--- /dev/null
+++ b/2018/09.pl
@@ -0,0 +1,13 @@
+#!/usr/bin/perl -w
+
+use v5.30;
+use strict;
+
+chomp (my $data = <>);
+
+my $re = join('|', map { ("\l$_\u$_", "\u$_\l$_") } ('a' .. 'z'));
+
+1 while $data =~ s/$re//;
+
+say length $data;
+