Year 2018

[aoc.git] / 2018 / 27.pl

diff --git a/2018/27.pl b/2018/27.pl
new file mode 100755 (executable)
index 0000000..5ef9f36
--- /dev/null
+++ b/2018/27.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/perl -w
+
+use v5.30;
+use strict;
+
+my $iters = shift @ARGV;
+$iters += 10;
+
+my @r = qw(3 7);
+my @p = qw(0 1);
+
+while (@r < $iters) {
+       my $n = $r[$p[0]] + $r[$p[1]];
+       push @r, split //, $n;
+       for (0 .. 1) {
+               $p[$_] += 1 + $r[$p[$_]];
+               $p[$_] -= @r while $p[$_] >= @r;
+       }
+       # say join ' ', @p, @r;
+}
+
+say join('', @r[-10 .. -1])
+