day 1

day1/day1.pl

@@ -0,0 +1,9 @@
+#!/usr/bin/env perl -n
+
+use 5.20.0;
+use List::AllUtils qw/ sum /;
+
+chomp;
+$_ .= substr $_, 0, 1;
+
+say sum /(.)(?=\1)/g;

day1/day1b.pl

@@ -0,0 +1,9 @@
+#!/usr/bin/env perl -n
+
+use 5.20.0;
+use List::AllUtils qw/ sum /;
+
+chomp;
+my @n = split '';
+
+say sum @n[ grep { $n[$_] == $n[($_+@n/2)%@n] }  0..$#n ]