Day 17

[aoc2020.git] / 33.pl

diff --git a/33.pl b/33.pl
new file mode 100755 (executable)
index 0000000..c8085ae
--- /dev/null
+++ b/33.pl
@@ -0,0 +1,75 @@
+#!/usr/bin/perl -w
+
+use strict;
+
+my $is_active;
+
+my ($min_x, $min_y, $min_z) = (-1, -1, -1);
+my ($max_x, $max_y, $max_z) = (0, 0, 1);
+
+my $y = 0;
+while (<>) {
+       chomp;
+       my $x = 0;
+       for (split //) {
+               $is_active->{"$x,$y,0"} = 1
+                       if $_ eq '#';
+               print "Active $x,$y,0\n";
+               $x++;
+       }
+       $max_x = $x;
+       $y++;
+}
+$max_y = $y;
+
+my $iter = 0;
+while ($iter < 6) {
+       my $new_active;
+       my ($new_min_x, $new_min_y, $new_min_z) = ($max_x, $max_y, $max_z);
+       my ($new_max_x, $new_max_y, $new_max_z) = ($min_x, $min_y, $min_z);
+       print "iter $iter x=$min_x:$max_x, y=$min_y:$max_y, z=$min_z:$max_z\n";
+       for my $z ($min_z .. $max_z) {
+       for my $y ($min_y .. $max_y) {
+       for my $x ($min_x .. $max_x) {
+               # print "Trying $x,$y,$z\n";
+               my $count = 0;
+               for my $neigh (
+                       [-1, -1, -1], [-1, -1, 0], [-1, -1, 1],
+                       [-1, 0, -1 ], [-1, 0, 0],  [-1, 0, 1],
+                       [-1, 1, -1 ], [-1, 1, 0],  [-1, 1, 1],
+                       [0,  -1, -1], [0,  -1, 0], [0,  -1, 1],
+                       [0,  0, -1 ],              [0,  0, 1],
+                       [0,  1, -1 ], [0,  1, 0],  [0,  1, 1],
+                       [1,  -1, -1], [1,  -1, 0], [1,  -1, 1],
+                       [1,  0, -1 ], [1,  0, 0],  [1,  0, 1],
+                       [1,  1, -1 ], [1,  1, 0],  [1,  1, 1],) {
+                       my ($nx, $ny, $nz) = @$neigh;
+                       $nx += $x; $ny += $y; $nz += $z;
+                       $count++ if $is_active->{"$nx,$ny,$nz"};
+               }
+               # print "$count neighbours\n";
+               if (($is_active->{"$x,$y,$z"} && ($count == 2 || $count == 3))
+                       || (!$is_active->{"$x,$y,$z"} && $count == 3)) {
+                       $new_active->{"$x,$y,$z"} = 1;
+                       # print "new active: $x, $y, $z\n";
+                       $new_min_x = $x if $x < $new_min_x;
+                       $new_min_y = $y if $y < $new_min_y;
+                       $new_min_z = $z if $z < $new_min_z;
+                       $new_max_x = $x if $x > $new_max_x;
+                       $new_max_y = $y if $y > $new_max_y;
+                       $new_max_z = $z if $z > $new_max_z;
+               }
+       } } }
+       $min_x = $new_min_x-1;
+       $min_y = $new_min_y-1;
+       $min_z = $new_min_z-1;
+       $max_x = $new_max_x+1;
+       $max_y = $new_max_y+1;
+       $max_z = $new_max_z+1;
+
+       $is_active = $new_active;
+       $iter++;
+}
+
+print "Acive: ", scalar keys %$is_active, "\n";
+