--- symmetry.pl	2007/08/26 10:59:01	4
+++ symmetry.pl	2007/08/31 14:28:27	11
@@ -30,6 +30,7 @@
 
 my @board = map { split(//) } split(/\n/, $board);
 my @trace;
+my @visited = (' ') x ($#board + 1);
 
 # line length
 my $ll = 8 * 2 + 1;
@@ -47,33 +48,66 @@
 # path traversed
 my @directions;
 
-my @found;
+my @shapes_found;
+
+my @shapes_start = ( '0,0' ); #( qw/0,0 1,0 0,3/ );
 
 sub draw {
 	my $o = 0;
-	my $out;
+	my $out = "\n  " . join('',
+		('0 1 2 3 4 5 6 7 8 | ') x 3
+	) . "\n";
 	while ( $o < $#board ) {
+		my $l = '|';
+		if ( $o % ($ll*2) == 0) {
+			my $y = int($o / ($ll*2));
+			$out .= "$y ";
+			$l = $y;
+		} else {
+			$out .= "  ";
+		}
+
 		$out .= join('', @board[ $o .. $o + $ll - 1 ]);
-		$out .= '   ';
+		$out .= " $l ";
 		$out .= join('', @trace[ $o .. $o + $ll - 1 ]);
-		$out .= "\n";
+		$out .= " $l ";
+		$out .= join('', @visited[ $o .. $o + $ll - 1 ]);
+		$out .= " $l\n";
 		$o += $ll;
 	}
+
+	$out .= "\n";
+
 	return $out;
 }
 
 sub trace {
 	warn "## trace $pos\n";
 	$trace[ $pos ] = $board[ $pos ];
+	$visited[$pos]++;
+}
+
+sub x_y {
+	my $p = shift;
+
+	$p ||= $pos;
+
+	my $y = int($p / ($ll*2));
+	my $x = int(($p % $ll) / 2);
+
+	warn "## x_y($p) -> $x,$y\n";
+
+#	return ($x,$y) if wantarray;
+	return "$x,$y";
 }
 
 sub move {
-	warn "move $step $step_name[$step]\n";
 	$pos += $move_by[ $step ];
 	trace;
 	$pos += $move_by[ $step ];
 	trace;
 	push @directions, $step;
+	warn "move $step $step_name[$step] to ", x_y, "\n";
 }
 
 sub follow {
@@ -84,6 +118,9 @@
 
 my $ok_path = qr/[\|\-]/;
 
+my @corners;
+my $corners_usage;
+
 sub can_turn {
 	my $try_step = shift;
 	die "no step?" unless defined $try_step;
@@ -94,15 +131,19 @@
 
 	my $old = $trace[ $turn_pos ];
 	$trace[ $turn_pos ] = '?';
-	warn "TEST\n",draw( @trace );
+	$trace[ $pos ] = '*';
+	warn "TEST ", x_y($turn_pos), "\n",draw;
 	$trace[ $turn_pos ] = $old;
 
 	if ( $board[ $turn_pos ] =~ $ok_path ) {
-		warn "OK can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos])";
+		my $xy = x_y($pos);
+		warn "OK can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos]) from $xy\n";
 		$step = $try_step;
+		push @corners, $xy;
+		$corners_usage->{$xy}++;
 		return 1;
 	} else {
-		warn "NOPE can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos])";
+		warn "NOPE can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos])\n";
 		return 0;
 	}
 }
@@ -123,12 +164,22 @@
 
 	$pos = $y * $ll * 2 + $x * 2;
 
-	warn "<<< shape from $x,$y pos: $pos\n";
 	@trace = ($unknown) x ( $#board + 1 );
 	@directions = ();
+	@corners = ();
 	trace;
 
 	my $len = 0;
+	$step = 0;
+
+	my $usage = $corners_usage->{"$x,$y"} || 0;
+
+	warn "<<< shape from $x,$y [usage: $usage] pos: $pos\n";
+
+	if ( $usage > 4 ) {
+		warn "SKIPPED, usage > 4\n";
+		return;
+	}
 
 	while( 1 ) {
 
@@ -147,29 +198,57 @@
 			warn "find line continuation from $step $step_name[$step]...\n";
 			can_turn( $step - 1 ) || can_turn( $step + 1 ) || die "can't find new direction";
 		}
-		warn draw( @trace );
+		warn draw;
 
 		if ( $debug ) {
 			print "WAIT> press enter | ",show_directions; my $foo = <STDIN>;
 		}
 	}
 
-	push @found, { x => $x, y => $y, len => $len, directions => show_directions };
+	push @shapes_found, { x => $x, y => $y, len => $len, directions => show_directions };
 
+	warn "### corners: ",join(' ', map { $_ . " [" . $corners_usage->{$_} . "]" } @corners),"\n";
 	warn ">>> ended at $pos, line length: $len, directions traversed: ",show_directions,"\n";
+
+	foreach my $c ( @corners ) {
+		if ( ! grep( /\Q$c\E/, @shapes_start ) ) {
+			warn "INFO: added corner $c as shape start\n";
+			push @shapes_start, $c;
+		}
+	}
+
 	print "WAIT> press enter"; my $foo = <STDIN>;
 
 	return $len;
 }
 
-my $shapes = '0,0 1,0 0,3';
+foreach my $start ( @shapes_start ) {
+	my ($x,$y) = split(/,/,$start);
+	if ( $x < 8 && $y < 8 ) {
+		my $len = shape( split(/,/,$start) );
+		warn "## $start has $len elements\n";
+	} else {
+		warn "SKIPPED $start\n";
+	}
+}
+
+sub is_symmetric {
+	my $path = shift || die "no path?";
 
-foreach my $start ( split(/\s/,$shapes) ) {
-	my $len = shape( split(/,/,$start) );
-	warn "## $start has $len elements\n";
+	my $h = length($path)/2;
+	return 0 if int($h) != $h;
+	my ($l,$r) = ( substr($path,0,$h), substr($path,$h) );
+	$r =~ tr/lrud/rldu/;
+#	warn "$l -- $r\n";
+	return 0 unless $l eq $r;
+	return 1;
 }
 
 print ">>> RESULTS:\n";
-foreach my $r ( @found ) {
-	printf "%2d,%-2d len: %-4d directions: %s\n", $r->{x}, $r->{y}, $r->{len}, $r->{directions};
+foreach my $r ( @shapes_found ) {
+	printf "%2d,%-2d len: %-4d directions: %s %s\n",
+	$r->{x}, $r->{y}, $r->{len},
+	is_symmetric($r->{directions}) ? 'OK' : '!!',
+	$r->{directions},
+	;
 }