From: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Date: Tue, 21 Dec 2021 06:19:47 +0000 (+0100)
Subject: Day 20: nothing to win, everything to lose
X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=aoc2021.git;a=commitdiff_plain;h=ccdd559ae858fd11c6f5adc2b33e738fab2fefef

Day 20: nothing to win, everything to lose
---

diff --git a/39.pl b/39.pl
new file mode 100755
index 0000000..e4d6c01
--- /dev/null
+++ b/39.pl
@@ -0,0 +1,76 @@
+#!/usr/bin/perl -w
+
+use v5.16;
+
+my @m = split //, <>;
+scalar <>;
+
+$; = ',';
+my @image = map { chomp; [ split // ] } <>;
+
+my $odd = 1;
+sub enhance {
+	my $img = shift;
+	my $ymax = @$img;
+	my $xmax = @{ $img->[0] };
+
+	say "odd=$odd, m0=$m[0]";
+
+	my @rv;
+	for my $y (0 .. $ymax+3) {
+		for my $x (0 .. $xmax+3) {
+			my $idx = 0;
+			for my $dy (-2 .. 0) {
+				my $y2 = $y+$dy;
+				for my $dx (-2 .. 0) {
+					my $x2 = $x+$dx;
+					# say "$x,$y + $dx,$dy = $x2, $y2";
+					$idx <<= 1;
+					if ($y2 >= 0 && $y2 < $ymax
+						&& $x2 >= 0 && $x2 < $xmax) {
+							$idx++ if $img->[$y2][$x2] eq '#';
+					} else {
+						$idx++ if !$odd && ($m[0] eq '#');
+					}
+				}
+			}
+			# say "$x,$y => $idx => $m[$idx]";
+			$rv[$y][$x] = $m[$idx];
+		}
+	}
+
+	$odd = !$odd;
+
+	return @rv;
+}
+
+sub imgdump {
+	my $img = shift;
+	my $ymax = @$img;
+	my $xmax = @{ $img->[0] };
+
+	my $sum;
+
+	say "$xmax x $ymax";
+	for my $y (0 .. $ymax-1) {
+		for my $x (0 .. $xmax-1) {
+			print $img->[$y][$x];
+			$sum++ if $img->[$y][$x] eq '#';
+		}
+		print "\n";
+	}
+	say "sum=$sum";
+}
+
+for (1 .. 50) {
+	imgdump(\@image);
+	@image = enhance(\@image);
+}
+imgdump(\@image);
+my $sum = 0;
+for my $row (@image) {
+	for my $pixel (@$row) {
+		$sum++ if $pixel eq '#';
+	}
+}
+say "pixels = $sum";