From b1a49a7c5412efa8eb15404ddaf9d132eed47f84 Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Mon, 18 Dec 2023 10:00:32 +0100
Subject: [PATCH] Day 18: quite fast program, but slow to write

---
 2023/35.pl | 76 +++++++++++++++++++++++++++++++++++++++++++
 2023/36.pl | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 171 insertions(+)
 create mode 100755 2023/35.pl
 create mode 100755 2023/36.pl

diff --git a/2023/35.pl b/2023/35.pl
new file mode 100755
index 0000000..307d9f4
--- /dev/null
+++ b/2023/35.pl
@@ -0,0 +1,76 @@
+#!/usr/bin/perl -w
+
+use v5.38;
+use experimental 'multidimensional';
+$; = ';';
+
+my ($x, $y) = (1000, 1000);
+my ($xmin, $xmax, $ymin, $ymax) = (1000) x 4;
+my %dir = (
+	R => [ 1,  0 ],
+	D => [ 0,  1 ],
+	L => [ -1, 0 ],
+	U => [ 0, -1 ],
+);
+
+my %map;
+while (<>) {
+	my ($dir, $len, $col) = /^(.) (\d+) \(\#(\w+)\)/;
+	say "at $x,$y dir $dir len $len col $col";
+	while ($len--){
+		$x += $dir{$dir}->[0];
+		$y += $dir{$dir}->[1];
+		say "    at $x,$y len $len";
+
+		$xmax = $x if $xmax < $x;
+		$ymax = $y if $ymax < $y;
+		$xmin = $x if $xmin > $x;
+		$ymin = $y if $ymin > $y;
+
+		$map{$x,$y} = $col;
+	}
+}
+
+say "$xmin..$xmax x $ymin..$ymax";
+
+my $sum;
+for my $y ($ymin .. $ymax) {
+	my $in = 0;
+	my $from = 0;
+	for my $x ($xmin .. $xmax) {
+		if ($map{$x,$y}) {
+			$sum++;
+			if ($map{$x,$y-1} && $map{$x,$y+1}) {
+				$in = !$in;
+				$from = 0;
+			} elsif ($map{$x,$y-1}) {
+				if ($from == 1) {
+					$in = !$in;
+					$from = 0;
+				} elsif ($from == 0) {
+					$from = -1;
+				} else {
+					$from = 0;
+				}
+			} elsif ($map{$x,$y+1}) {
+				if ($from == -1) {
+					$in = !$in;
+					$from = 0;
+				} elsif ($from == 0) {
+					$from = 1;
+				} else {
+					$from = 0;
+				}
+			}
+			print '#';
+		} else {
+			$sum++ if $in;
+			print $map{$x,$y} || $in ? 'O' : '.';
+		}
+	}
+	print "\n";
+}
+
+
+asay $sum;
+
diff --git a/2023/36.pl b/2023/36.pl
new file mode 100755
index 0000000..956c980
--- /dev/null
+++ b/2023/36.pl
@@ -0,0 +1,95 @@
+#!/usr/bin/perl -w
+
+use v5.38;
+
+my ($x, $y) = (20_000_000, 20_000_000);
+my %dir = (
+	0 => [ 1,  0 ],
+	1 => [ 0,  1 ],
+	2 => [ -1, 0 ],
+	3 => [ 0, -1 ],
+);
+
+my %map;
+my %dirs;
+while (<>) {
+	my ($len, $dir) = /\(\#(\w+)(\w)\)/;
+	$len = hex $len;
+	$map{$y}{$x} |= (1 << $dir);
+	$x += $len * $dir{$dir}->[0];
+	$y += $len * $dir{$dir}->[1];
+	$map{$y}{$x} |= (1 << ($dir ^ 2));
+	say "at $x,$y dir $dir len $len";
+}
+
+sub sum_int {
+	my @pts = @_;
+	my $sum = 0;
+	my $in;
+	my $prev;
+	for my $pt (@pts) {
+		if (defined $prev && $in) {
+			$sum += $pt - $prev + 1;
+		}
+		$prev = $pt;
+		$in = !$in;
+	}
+	return $sum;
+}
+
+my @pts;
+my $y0;
+my $sum;
+for my $y1 (sort { $a <=> $b } keys %map) {
+	say "y $y1";
+	my $in;
+	my $x0;
+	my @nx;
+	my @tx;
+	my $rowsum;
+	if (defined $y0) {
+		my $psum = sum_int(@pts);
+		$sum += ($y1-$y0-1) * $psum;
+	}
+
+	for my $x1 (sort { $a <=> $b } (@pts, keys %{ $map{$y1} })) {
+		next if $x0 && $x1 == $x0;
+		my $d = $map{$y1}{$x1};
+		my $d0 = $map{$y1}{$x0} if defined $x0;
+		say " at $x1,$y1 ", $d // "|";
+		push @nx, $x1
+			if !defined $d || ($d & 2);
+		if (!defined $d) {
+			push @tx, $x1;
+		} elsif ($d & 4) {
+			if (@tx & 1) {
+				if (($d0 == 9 && $d == 6) || ($d0 == 3 && $d == 12)) {
+					push @tx, $x1;
+				}
+			} else {
+				push @tx, $x0;
+				if (($d0 == 9 && $d == 12) || ($d0 == 3 && $d == 6)) {
+					push @tx, $x1;
+				}
+			}
+		}
+
+		if (defined $x0) {
+			say "   int $x0 .. $x1";
+			
+			$in = !$in;
+			if ($in) {
+				$rowsum += $x1 - $x0 + 1;
+			}
+		}
+		$x0 = $x1;
+	}
+	$sum += sum_int(@tx);
+	say " tx=@tx sum ", sum_int(@tx);
+	say " nx=@nx sum ", sum_int(@nx);
+	@pts = @nx;
+	$y0 = $y1;
+}
+
+say $sum;
+
-- 
2.43.5