Day 12

[aoc2020.git] / 24.pl

diff --git a/24.pl b/24.pl
new file mode 100755 (executable)
index 0000000..29b1fdf
--- /dev/null
+++ b/24.pl
@@ -0,0 +1,38 @@
+#!/usr/bin/perl -w
+
+use strict;
+
+my ($wx, $wy, $x, $y) = (10, 1);
+
+while (<>) {
+       my ($cmd, $num) = /\A(.)(\d+)/;
+       print "cmd=$cmd, num=$num: ";
+       if ($cmd eq 'F') {
+               $x += $num*$wx;
+               $y += $num*$wy;
+       } elsif ($cmd eq 'R') {
+               while (($num -= 90) >= 0) {
+                       my $tmp = $wx;
+                       $wx = $wy;
+                       $wy = -$tmp;
+               }
+       } elsif ($cmd eq 'L') {
+               while (($num -= 90) >= 0) {
+                       my $tmp = $wy;
+                       $wy = $wx;
+                       $wx = -$tmp;
+               }
+       } elsif ($cmd eq 'N') {
+               $wy += $num;
+       } elsif ($cmd eq 'S') {
+               $wy -= $num;
+       } elsif ($cmd eq 'E') {
+               $wx += $num;
+       } elsif ($cmd eq 'W') {
+               $wx -= $num;
+       }
+       print " at ($x, $y, $wx, $wy)\n";
+}
+
+print abs($x) + abs($y), "\n";
+