2 files changed, 45 insertions, 0 deletions
diff --git a/2018/02/puzzle-1.pl b/2018/02/puzzle-1.pl
new file mode 100755
index 0000000..85a533b
--- /dev/null
+++ b/2018/02/puzzle-1.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+my $file = "input";
+open my $in, "<", $file or die "Failed to open ‘$file’: $!";
+
+my ($x, $y) = (0) x 2;
+while (<$in>) {
+	chomp;
+	my %freq;
+	$freq{$_}++ for split //;
+	$x++ if grep { $_ == 2 } values %freq;
+	$y++ if grep { $_ == 3 } values %freq;
+}
+
+close $in;
+printf "%d\n", $x * $y;
diff --git a/2018/02/puzzle-2.py b/2018/02/puzzle-2.py
new file mode 100755
index 0000000..37ce920
--- /dev/null
+++ b/2018/02/puzzle-2.py
@@ -0,0 +1,26 @@
+#!/usr/bin/python3
+
+import itertools
+
+
+def main() -> None:
+    with open('input', 'r') as f:
+        xs = f.readlines()
+    print(next(
+        x for x in
+        itertools.starmap(common, itertools.combinations(xs, 2))
+        if x is not None
+    ), end='')
+
+
+def common(x: str, y: str) -> str | None:
+    it = (i for i, (a, b) in enumerate(zip(x, y)) if a != b)
+    i = next(it)
+    try:
+        next(it)
+    except StopIteration:
+        return x[:i] + x[i+1:]
+
+
+if __name__ == '__main__':
+    main()