X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=blobdiff_plain;f=2023%2F28.pl;h=f0547dd171265e0e3348d555573bd006128570e8;hb=cb7662a16eca1ff55e28338ef8ea7161224ac078;hp=7135ca558336ee5b39994d2d2cff5c5ab335fadf;hpb=9df28e43f93ba69cba3f7f56dbb1b77235ad7413;p=aoc.git

diff --git a/2023/28.pl b/2023/28.pl
index 7135ca5..f0547dd 100755
--- a/2023/28.pl
+++ b/2023/28.pl
@@ -2,91 +2,22 @@
 
 use v5.38;
 
-my @map = map { chomp; [ split // ] } <>;
-my $xmax = $#{ $map[0] };
-my $ymax = $#map;
+my $map; { local $/; $map = <>; }
 
-my %seen;
-my @rounds;
-my $round;
-while (1) {
-	$round++;
-	my $retry;
-	$retry = 1;
-	while ($retry) {
-		$retry = 0;
-		for my $y (1 .. $ymax) {
-			for my $x (0 .. $xmax) {
-				if ($map[$y][$x] eq 'O' && $map[$y-1][$x] eq '.') {
-					$map[$y-1][$x] = 'O';
-					$map[$y][$x] = '.';
-					$retry = 1;
-				}
-			}
-		}
+my (@score, %seen, $round);
+while (!$seen{$map}) {
+	$seen{$map} = $round++;
+	for (1 .. 4) {
+		my $map1;
+		do { # rotate the map:
+			$map1 .= join('', reverse $map =~ /^./gm) . "\n"
+		} while $map =~ s/^.//gm;
+		chomp ($map = $map1);
+		1 while $map =~ s/O(\.+)/$1O/g; # move O's to the right
 	}
-	$retry = 1;
-	while ($retry) {
-		$retry = 0;
-		for my $x (1 .. $xmax) {
-			for my $y (0 .. $ymax) {
-				if ($map[$y][$x] eq 'O' && $map[$y][$x-1] eq '.') {
-					$map[$y][$x-1] = 'O';
-					$map[$y][$x] = '.';
-					$retry = 1;
-				}
-			}
-		}
-	}
-	$retry = 1;
-	while ($retry) {
-		$retry = 0;
-		for my $y (reverse 0 .. $ymax-1) {
-			for my $x (0 .. $xmax) {
-				if ($map[$y][$x] eq 'O' && $map[$y+1][$x] eq '.') {
-					$map[$y+1][$x] = 'O';
-					$map[$y][$x] = '.';
-					$retry = 1;
-				}
-			}
-		}
-	}
-	$retry = 1;
-	while ($retry) {
-		$retry = 0;
-		for my $x (reverse 0 .. $xmax-1) {
-			for my $y (0 .. $ymax) {
-				if ($map[$y][$x] eq 'O' && $map[$y][$x+1] eq '.') {
-					$map[$y][$x+1] = 'O';
-					$map[$y][$x] = '.';
-					$retry = 1;
-				}
-			}
-		}
-	}
-		
-	# say join('', @$_) for @map;
-
-	my $sum;
-	for my $y (0 .. $ymax) {
-		for my $x (0 .. $xmax) {
-			$sum += $ymax + 1 - $y if $map[$y][$x] eq 'O';
-		}
-	}
-	say $sum;
-	$rounds[$round] = $sum;
-	say "round $round sum $sum";
-	my $map = join("\n", map { join('', @$_) } @map);
-	if ($seen{$map}) {
-		say "round $round seen also at $seen{$map}";
-		my $period = $round - $seen{$map};
-		my $total = 1000000000;
-		$total -= $round;
-		$total %= $period;
-		say "looking at ", $round - $period + $total;
-		say $rounds[$round-$period+$total];
-		last;
-	}
-	$seen{$map} = $round;
+	$score[$round] +=()= substr($map, pos($map)) =~ /\n/g
+		while $map =~ /O/g;
 }
 
+my $remains = (1000000000 - $round) % ($round - $seen{$map});
+say $score[$seen{$map} + $remains];