viewvc.cgi/symmetry-circle/symmetry.pl

#!/usr/bin/perl -w

# symmetry.pl
#
# 08/26/07 02:40:37 CEST Dobrica Pavlinusic <dpavlin@rot13.org>

use strict;

my $board = << '_BOARD_';
+-+-+-+-+-+-+-+-+
| |   |o| |     |
+ +   +-+ +-+   |
|o|   |  o  | o |
+ +   +-+ +-+   |
| |  o  | |     |
+-+-+   +-+-+-+-+
|   |   |o|     |
+-+ +   +-+-+ +-+
| |o|   |o|o|o|o|
+ + +-+-+-+-+ +-+
|o|   |   |     |
+ +-+-+-+-+-+-+-+
| |      o      |
+-+-+-+-+-+-+-+-+
|    o    |  o  |
+-+-+-+-+-+-+-+-+
_BOARD_

my $debug = shift @ARGV || 0;

my @board = map { split(//) } split(/\n/, $board);
my @trace;
my @visited = (' ') x ($#board + 1);

# line length
my $ll = 8 * 2 + 1;

my @step_name = ( qw/right down left up/ );
my @move_by = ( 1, $ll, -1, -$ll );
my $step = 0;   # right

# offset 0, top-left corner
my $pos = 0;

# unknown trace position
my $unknown = ' ';

# path traversed
my @directions;

my @shapes_found;

my @shapes_start = ( '0,0' ); #( qw/0,0 1,0 0,3/ );

sub draw {
        my $o = 0;
        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 .= " $l ";
                $out .= join('', @trace[ $o .. $o + $ll - 1 ]);
                $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 {
        $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 {
        $step = shift;
        $step %= 4;
        warn "follow $step $step_name[$step]\n";
}

my $ok_path = qr/[\|\-]/;

my @corners;

sub can_turn {
        my $try_step = shift;
        die "no step?" unless defined $try_step;

        $try_step %= 4;

        my $turn_pos = $pos + $move_by[$try_step];

        my $old = $trace[ $turn_pos ];
        $trace[ $turn_pos ] = '?';
        $trace[ $pos ] = '*';
        warn "TEST ", x_y($turn_pos), "\n",draw;
        $trace[ $turn_pos ] = $old;

        if ( $board[ $turn_pos ] =~ $ok_path ) {
                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;
                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])\n";
                return 0;
        }
}

sub show_directions {
        return 
                join('',
                        map {
                                substr($step_name[$_],0,1)
                        } @directions
                )
        ;
}

sub shape {

        my ($x,$y) = @_;

        $pos = $y * $ll * 2 + $x * 2;

        @trace = ($unknown) x ( $#board + 1 );
        @directions = ();
        @corners = ();
        trace;

        my $len = 0;
        $step = 0;

        warn "<<< shape from $x,$y pos: $pos\n";

        while( 1 ) {

                my $next_pos = $pos + $move_by[ $step ];
                warn "# pos: $pos next_pos: $next_pos step: $step $step_name[$step] trace: ",show_directions,"\n";

                if ( $trace[ $next_pos ] ne $unknown ) {
                        warn "position $next_pos re-visited, exiting\n";
                        last;
                } elsif ( $board[ $next_pos ] =~ $ok_path ) {
                        warn "OK next_pos = $next_pos b($board[$next_pos]) t($trace[$next_pos])\n";
                        move;
                        $len++;
                        can_turn( $step + 1 );
                } else {
                        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;

                if ( $debug ) {
                        print "WAIT> press enter | ",show_directions; my $foo = <STDIN>;
                }
        }

        push @shapes_found, { x => $x, y => $y, len => $len, directions => show_directions };

        warn "### corners: ",join(' ', @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;
}

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";
        }
}

print ">>> RESULTS:\n";
foreach my $r ( @shapes_found ) {
        printf "%2d,%-2d len: %-4d directions: %s\n", $r->{x}, $r->{y}, $r->{len}, $r->{directions};
}
1	dpavlin	1	#!/usr/bin/perl -w
2
3			# symmetry.pl
4			#
5			# 08/26/07 02:40:37 CEST Dobrica Pavlinusic <dpavlin@rot13.org>
6
7			use strict;
8
9			my $board = << '_BOARD_';
10			+-+-+-+-+-+-+-+-+
11			\| \| \|o\| \| \|
12			+ + +-+ +-+ \|
13			\|o\| \| o \| o \|
14			+ + +-+ +-+ \|
15			\| \| o \| \| \|
16			+-+-+ +-+-+-+-+
17			\| \| \|o\| \|
18			+-+ + +-+-+ +-+
19			\| \|o\| \|o\|o\|o\|o\|
20			+ + +-+-+-+-+ +-+
21			\|o\| \| \| \|
22			+ +-+-+-+-+-+-+-+
23			\| \| o \|
24			+-+-+-+-+-+-+-+-+
25			\| o \| o \|
26			+-+-+-+-+-+-+-+-+
27			_BOARD_
28
29	dpavlin	4	my $debug = shift @ARGV \|\| 0;
30
31	dpavlin	1	my @board = map { split(//) } split(/\n/, $board);
32	dpavlin	3	my @trace;
33	dpavlin	6	my @visited = (' ') x ($#board + 1);
34	dpavlin	1
35			# line length
36			my $ll = 8 * 2 + 1;
37
38	dpavlin	3	my @step_name = ( qw/right down left up/ );
39			my @move_by = ( 1, $ll, -1, -$ll );
40			my $step = 0; # right
41
42			# offset 0, top-left corner
43			my $pos = 0;
44
45			# unknown trace position
46			my $unknown = ' ';
47
48	dpavlin	4	# path traversed
49			my @directions;
50
51	dpavlin	5	my @shapes_found;
52	dpavlin	4
53	dpavlin	5	my @shapes_start = ( '0,0' ); #( qw/0,0 1,0 0,3/ );
54
55	dpavlin	1	sub draw {
56			my $o = 0;
57	dpavlin	6	my $out = "\n " . join('',
58			('0 1 2 3 4 5 6 7 8 \| ') x 3
59			) . "\n";
60	dpavlin	1	while ( $o < $#board ) {
61	dpavlin	6	my $l = '\|';
62			if ( $o % ($ll*2) == 0) {
63			my $y = int($o / ($ll*2));
64			$out .= "$y ";
65			$l = $y;
66			} else {
67			$out .= " ";
68			}
69
70	dpavlin	3	$out .= join('', @board[ $o .. $o + $ll - 1 ]);
71	dpavlin	6	$out .= " $l ";
72	dpavlin	3	$out .= join('', @trace[ $o .. $o + $ll - 1 ]);
73	dpavlin	6	$out .= " $l ";
74			$out .= join('', @visited[ $o .. $o + $ll - 1 ]);
75			$out .= " $l\n";
76	dpavlin	1	$o += $ll;
77			}
78	dpavlin	6
79			$out .= "\n";
80
81	dpavlin	1	return $out;
82			}
83
84			sub trace {
85	dpavlin	3	warn "## trace $pos\n";
86	dpavlin	1	$trace[ $pos ] = $board[ $pos ];
87	dpavlin	6	$visited[$pos]++;
88	dpavlin	1	}
89
90	dpavlin	6	sub x_y {
91			my $p = shift;
92	dpavlin	5
93	dpavlin	7	$p \|\|= $pos;
94	dpavlin	5
95	dpavlin	6	my $y = int($p / ($ll*2));
96			my $x = int(($p % $ll) / 2);
97	dpavlin	5
98	dpavlin	7	warn "## x_y($p) -> $x,$y\n";
99	dpavlin	5
100	dpavlin	6	# return ($x,$y) if wantarray;
101	dpavlin	5	return "$x,$y";
102			}
103
104	dpavlin	1	sub move {
105			$pos += $move_by[ $step ];
106			trace;
107			$pos += $move_by[ $step ];
108			trace;
109	dpavlin	4	push @directions, $step;
110	dpavlin	6	warn "move $step $step_name[$step] to ", x_y, "\n";
111	dpavlin	1	}
112
113			sub follow {
114			$step = shift;
115			$step %= 4;
116			warn "follow $step $step_name[$step]\n";
117			}
118
119			my $ok_path = qr/[\\|\-]/;
120
121	dpavlin	7	my @corners;
122
123	dpavlin	1	sub can_turn {
124	dpavlin	2	my $try_step = shift;
125			die "no step?" unless defined $try_step;
126	dpavlin	1
127	dpavlin	2	$try_step %= 4;
128	dpavlin	1
129	dpavlin	2	my $turn_pos = $pos + $move_by[$try_step];
130
131	dpavlin	1	my $old = $trace[ $turn_pos ];
132			$trace[ $turn_pos ] = '?';
133	dpavlin	6	$trace[ $pos ] = '*';
134			warn "TEST ", x_y($turn_pos), "\n",draw;
135	dpavlin	1	$trace[ $turn_pos ] = $old;
136
137			if ( $board[ $turn_pos ] =~ $ok_path ) {
138	dpavlin	8	my $xy = x_y($pos);
139			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";
140	dpavlin	2	$step = $try_step;
141	dpavlin	7	push @corners, $xy;
142	dpavlin	1	return 1;
143			} else {
144	dpavlin	5	warn "NOPE can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos])\n";
145	dpavlin	1	return 0;
146			}
147			}
148
149	dpavlin	4	sub show_directions {
150			return
151			join('',
152			map {
153			substr($step_name[$_],0,1)
154			} @directions
155			)
156			;
157			}
158
159	dpavlin	3	sub shape {
160	dpavlin	1
161	dpavlin	3	my ($x,$y) = @_;
162	dpavlin	1
163	dpavlin	3	$pos = $y * $ll * 2 + $x * 2;
164
165			@trace = ($unknown) x ( $#board + 1 );
166	dpavlin	4	@directions = ();
167	dpavlin	7	@corners = ();
168	dpavlin	3	trace;
169
170			my $len = 0;
171	dpavlin	6	$step = 0;
172	dpavlin	3
173	dpavlin	6	warn "<<< shape from $x,$y pos: $pos\n";
174
175	dpavlin	3	while( 1 ) {
176
177			my $next_pos = $pos + $move_by[ $step ];
178	dpavlin	4	warn "# pos: $pos next_pos: $next_pos step: $step $step_name[$step] trace: ",show_directions,"\n";
179	dpavlin	3
180			if ( $trace[ $next_pos ] ne $unknown ) {
181			warn "position $next_pos re-visited, exiting\n";
182			last;
183			} elsif ( $board[ $next_pos ] =~ $ok_path ) {
184			warn "OK next_pos = $next_pos b($board[$next_pos]) t($trace[$next_pos])\n";
185			move;
186			$len++;
187			can_turn( $step + 1 );
188			} else {
189			warn "find line continuation from $step $step_name[$step]...\n";
190			can_turn( $step - 1 ) \|\| can_turn( $step + 1 ) \|\| die "can't find new direction";
191			}
192	dpavlin	6	warn draw;
193	dpavlin	3
194	dpavlin	4	if ( $debug ) {
195			print "WAIT> press enter \| ",show_directions; my $foo = <STDIN>;
196			}
197	dpavlin	1	}
198
199	dpavlin	5	push @shapes_found, { x => $x, y => $y, len => $len, directions => show_directions };
200	dpavlin	4
201	dpavlin	7	warn "### corners: ",join(' ', @corners),"\n";
202			warn ">>> ended at $pos, line length: $len, directions traversed: ",show_directions,"\n";
203	dpavlin	5
204	dpavlin	7	foreach my $c ( @corners ) {
205			if ( ! grep( /\Q$c\E/, @shapes_start ) ) {
206			warn "INFO: added corner $c as shape start\n";
207			push @shapes_start, $c;
208			}
209	dpavlin	5	}
210
211	dpavlin	4	print "WAIT> press enter"; my $foo = <STDIN>;
212
213	dpavlin	3	return $len;
214	dpavlin	1	}
215
216	dpavlin	5	foreach my $start ( @shapes_start ) {
217	dpavlin	7	my ($x,$y) = split(/,/,$start);
218			if ( $x < 8 && $y < 8 ) {
219			my $len = shape( split(/,/,$start) );
220			warn "## $start has $len elements\n";
221			} else {
222			warn "SKIPPED $start\n";
223			}
224	dpavlin	3	}
225	dpavlin	4
226			print ">>> RESULTS:\n";
227	dpavlin	5	foreach my $r ( @shapes_found ) {
228	dpavlin	4	printf "%2d,%-2d len: %-4d directions: %s\n", $r->{x}, $r->{y}, $r->{len}, $r->{directions};
229			}