Moved 2020 to a subdir

[aoc.git] / 2020 / 20.pl

diff --git a/2020/20.pl b/2020/20.pl
new file mode 100755 (executable)
index 0000000..09210e2
--- /dev/null
+++ b/2020/20.pl
@@ -0,0 +1,26 @@
+#!/usr/bin/perl -w
+
+use strict;
+use Data::Dumper;
+
+local $/;
+my @ads = sort { $a <=> $b } map { chomp; $_ } split /\n/, <>;
+
+my $prev = 0;
+my $ones = 0;
+my $total = 1;
+my @ones2count = qw(1 1 2 4 7);
+push @ads, $ads[-1]+3;
+for my $n (@ads) {
+       if ($n - $prev == 1) {
+               $ones++;
+       } else {
+               print "$ones ones + 3, total=$total*$ones2count[$ones]\n";
+               $total *= $ones2count[$ones];
+               $ones = 0;
+       }
+       $prev = $n;
+}
+
+print "total=$total\n";
+