X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=aoc2020.git;a=blobdiff_plain;f=40.pl;h=074e56152106287dd84e4420d59c428cfeac882d;hp=df479d91baa74f58b8d4e6935eee2b2eb1de1fe5;hb=HEAD;hpb=3dcbc8cbbed0a020192974ba29b73f0164b49ce2

diff --git a/40.pl b/40.pl
index df479d9..074e561 100755
--- a/40.pl
+++ b/40.pl
@@ -2,157 +2,123 @@
 
 use strict;
 
-local $/ = "\n\n";
+sub rows2str {
+	my (@rows) = @_;
+	return join("\n", @rows) . "\n";
+}
 
-sub rev {
-	my ($in) = @_;
-	return join('', reverse split //, $in);
+sub rotate {
+	my ($str) = (@_);
+	my $dim =()= $str =~ /(\n)/g;
+	my $newstr = '';
+	for my $y (0 .. $dim-1) {
+		for my $x (0 .. $dim-1) {
+			$newstr .= substr($str, $y + ($dim+1)*($dim - $x - 1), 1);
+		}
+		$newstr .= "\n";
+	}
+	return $newstr;
 }
 
+sub flip {
+	my ($str) = @_;
+	return rows2str(map { join('', reverse split //) } split /\n/, $str);
+}
+
+sub rotate_or_flip {
+	my ($str, $count) = @_;
+	return $count == 4 ? flip($str) : rotate($str);
+}
+
+sub trim {
+	my ($str) = @_;
+	my @rows = split /\n/, $str;
+	shift @rows;
+	pop @rows;
+	return map { s/\A.//; s/.\z//; $_ } @rows;
+}
+
+sub top_side {
+	$_[0] =~ /\A(.*?)\n/xms;
+	return $1;
+}
+
+sub bottom_side {
+	$_[0] =~ /\A.*\n(.*?)\n\z/xms;
+	return $1;
+}
+
+sub left_side {
+	return join('', map { substr($_, 0, 1) } split /\n/, $_[0]);
+}
+
+sub right_side {
+	return join('', map { substr($_, -1, 1) } split /\n/, $_[0]);
+}
+
+my (%top2tile, %left2tile);
+
+local $/ = "\n\n";
 
-my %tiles;
-my %sides;
-my %side2tiles;
 while (<>) {
-	my ($id, @rows) = split /\n/;
-	$id =~ s/Tile //;
-	$id =~ s/://;
-	$tiles{$id} = \@rows;
-	$sides{$id} = [
-		$rows[0],
-		join('', map { substr($_, -1, 1) } @rows),
-		rev($rows[-1]),
-		rev(join('', map { substr($_, 0, 1) } @rows)),
-	];
-	print "Tile <$id> sides ", join(' ', @{ $sides{$id} }), "\n";
-	my $i = 0;
-	for my $side (@{ $sides{$id} }) {
-		$side2tiles{$side}->{$id} = $i;
-		$side2tiles{rev($side)}->{$id} = $i+4;
-		$i++;
+	my ($id, $data) = /\ATile\s+(\d+):\n(.*?\n)\n?\z/xms;
+	for (1 .. 8) {
+		push @{ $top2tile{top_side($data)} }, [ $id, $data ];
+		push @{ $left2tile{left_side($data)} }, [ $id, $data ];
+		$data = rotate_or_flip($data, $_);
 	}
 }
 
+# computed in 39.pl
 my $dim = 12;
-my $next = '###.#.#...';
+my $top_row = '###.#.#...';
 
 # my $dim = 3;
-# my $next = '#...##.#..';
-my $next_id = -1;
-my $map;
-my %seen;
+# my $top_row = '#...##.#..';
+
+my $top_id = -1;
+my @map_rows;
+my $data;
 
 for my $y (0 .. $dim-1) {
-	my ($id) = grep { $_ != $next_id } keys %{ $side2tiles{$next} };
-	my $side = $side2tiles{$next}->{$id};
-	$map->[$y][0] = [ $id, $side ];
-	die "$id seen again\n"
-		if $seen{$id};
-	$seen{$id} = 1;
-	my $next_side = $side > 3
-		? (($side - 1) & 3)
-		: ($side + 1) & 3;
-	$next = $sides{$id}->[$next_side];
-	$next = rev($next) if $side > 3;
-	my $top_side = $side;
-	print "id=$id, side=$side, next_side=$next_side, top_side=$top_side, next=|$next|\n";
-	$next_id = $id;
-	
-	for my $x (1 .. $dim-1) {
-		($id) = grep { $_ != $next_id } keys %{ $side2tiles{$next} };
-		$side = $side2tiles{$next}->{$id};
-		die "$id seen again\n"
-			if $seen{$id};
-		$seen{$id} = 1;
-		my $top_side = ((($side & 3) + (($side >> 2) ? 1 : -1)) & 3) | (($side & 4) ^ 4);
-		$map->[$y][$x] = [ $id, $top_side ];
-		$next_side = (($side + 2) & 3);
-		$next = $sides{$id}->[$next_side];
-		$next = rev($next) if $side < 4;
-		$next_id = $id;
-		print "id=$id, side=$side, next_side=$next_side, top_side=$top_side, next=|$next|\n";
-	}
+	my ($id)  = grep { $_->[0] != $top_id } @{ $top2tile{$top_row} };
+	($top_id, $data) = @$id;
+	$top_row = bottom_side($data);
 
-	print "\n";
+	push @map_rows, trim($data);
 
-	($next_id, $next_side) = @{ $map->[$y][0] };
-	$next = $sides{$next_id}->[($next_side + 2) & 3];
-	$next = rev($next) if $next_side < 4;
-	print "bottom side of $next_id = |$next|\n";
-}
+	my $right_id = $top_id;
+	my $right_row = right_side($data);
+
+	for my $x (1 .. $dim-1) {
+		my ($id) = grep { $_->[0] != $right_id } @{ $left2tile{$right_row} };
+		($right_id, $data) = @$id;
+		$right_row = right_side($data);
 
-my $shortmap = '';
-for my $y (0 .. 8*$dim-1) {
-	my $y1 = 1 + ($y % 8);
-	for my $x (0 .. 8*$dim-1) {
-		my $x1 = 1 + ($x % 8);
-		my ($id, $or) = @{ $map->[int($y/8)][int($x/8)] };
-		my ($x2, $y2) = ($x1, $y1);
-		if ($or == 1) {
-			($x2, $y2) = (9-$y1, $x1);
-		} elsif ($or == 2) {
-			($x2, $y2) = (9-$x1, 9-$y1);
-		} elsif ($or == 3) {
-			($x2, $y2) = ($y1, 9-$x1);
-		} elsif ($or == 4) {
-			($x2, $y2) = (9-$x1, $y1);
-		} elsif ($or == 5) {
-			($x2, $y2) = (9-$y1, 9-$x1);
-		} elsif ($or == 6) {
-			($x2, $y2) = ($x1, 9-$y1);
-		} elsif ($or == 7) {
-			($x2, $y2) = ($y1, $x1);
+		my $i = @map_rows - 8;
+		for (trim($data)) {
+			$map_rows[$i++] .= $_;
 		}
-		$shortmap .= substr($tiles{$id}->[$y2], $x2, 1);
 	}
-	$shortmap .= "\n";
 }
 
-print join("\n", $shortmap), "\n";
-
-my $monster = join('[\.#\n]' x ($dim * 8 - 20 + 1), map { $a=$_; $a=~ s/\./[\.#]/g; $a } 
-	 '..................#.',
-	'#....##....##....###',
-	'.#..#..#..#..#..#...'
-);
-
-$monster = ".(?=$monster)";
-print "monster=$monster\n";
-
-for (1 .. 2) {
-	for (1 .. 4) {
-		my $count;
-		if (my $count =()= $shortmap =~ /($monster)/g) {
-			print "$count matches\n";
-			my $hashes =()= $shortmap =~ /#/g;
-			print "$hashes-$count*15=", $hashes-$count*15, "\n";
-			exit 0;
-		}
-		my $newmap = '';
-		for my $y (0 .. 8*$dim-1) {
-			for my $x (0 .. 8*$dim-1) {
-				print "$x,$y\n";
-				$newmap .= substr($shortmap,
-					$y + (8*$dim+1)*(8*$dim-$x-1), 1);
-			}
-			$newmap .= "\n";
-		}
-		print "\nRotate:\n$newmap\n";
-		$shortmap = $newmap;
-	}
-	my $newmap;
-	for my $y (0 .. 8*$dim-1) {
-		for my $x (0 .. 8*$dim-1) {
-			$newmap .= substr($shortmap,
-				$x + (8*$dim+1)*(8*$dim-$y-1), 1);
-		}
-		$newmap .= "\n";
+my $map = rows2str(@map_rows);
+my $hashes =()= $map =~ /#/g;
+
+my $monster = '.(?='
+	. join('[\.#\n]' x ($dim * 8 - 20 + 1),
+		map { my $a=$_; $a=~ s/\./[\.#]/g; $a }
+		 '..................#.',
+		'#....##....##....###',
+		'.#..#..#..#..#..#...'
+	) . ')';
+
+for (1 .. 8) {
+	if (my $count =()= $map =~ /($monster)/g) {
+		print "$count matches\n";
+		print "$hashes-$count*15=", $hashes-$count*15, "\n";
+		exit 0;
 	}
-	$shortmap = $newmap;
-	print "\nFlip:\n$newmap\n";
-
+	$map = rotate_or_flip($map, $_);
 }
 
-		
-
-