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 |
my $debug = shift @ARGV || 0; |
30 |
|
31 |
my @board = map { split(//) } split(/\n/, $board); |
32 |
my @trace; |
33 |
|
34 |
# line length |
35 |
my $ll = 8 * 2 + 1; |
36 |
|
37 |
my @step_name = ( qw/right down left up/ ); |
38 |
my @move_by = ( 1, $ll, -1, -$ll ); |
39 |
my $step = 0; # right |
40 |
|
41 |
# offset 0, top-left corner |
42 |
my $pos = 0; |
43 |
|
44 |
# unknown trace position |
45 |
my $unknown = ' '; |
46 |
|
47 |
# path traversed |
48 |
my @directions; |
49 |
|
50 |
my @found; |
51 |
|
52 |
sub draw { |
53 |
my $o = 0; |
54 |
my $out; |
55 |
while ( $o < $#board ) { |
56 |
$out .= join('', @board[ $o .. $o + $ll - 1 ]); |
57 |
$out .= ' '; |
58 |
$out .= join('', @trace[ $o .. $o + $ll - 1 ]); |
59 |
$out .= "\n"; |
60 |
$o += $ll; |
61 |
} |
62 |
return $out; |
63 |
} |
64 |
|
65 |
sub trace { |
66 |
warn "## trace $pos\n"; |
67 |
$trace[ $pos ] = $board[ $pos ]; |
68 |
} |
69 |
|
70 |
sub move { |
71 |
warn "move $step $step_name[$step]\n"; |
72 |
$pos += $move_by[ $step ]; |
73 |
trace; |
74 |
$pos += $move_by[ $step ]; |
75 |
trace; |
76 |
push @directions, $step; |
77 |
} |
78 |
|
79 |
sub follow { |
80 |
$step = shift; |
81 |
$step %= 4; |
82 |
warn "follow $step $step_name[$step]\n"; |
83 |
} |
84 |
|
85 |
my $ok_path = qr/[\|\-]/; |
86 |
|
87 |
sub can_turn { |
88 |
my $try_step = shift; |
89 |
die "no step?" unless defined $try_step; |
90 |
|
91 |
$try_step %= 4; |
92 |
|
93 |
my $turn_pos = $pos + $move_by[$try_step]; |
94 |
|
95 |
my $old = $trace[ $turn_pos ]; |
96 |
$trace[ $turn_pos ] = '?'; |
97 |
warn "TEST\n",draw( @trace ); |
98 |
$trace[ $turn_pos ] = $old; |
99 |
|
100 |
if ( $board[ $turn_pos ] =~ $ok_path ) { |
101 |
warn "OK can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos])"; |
102 |
$step = $try_step; |
103 |
return 1; |
104 |
} else { |
105 |
warn "NOPE can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos])"; |
106 |
return 0; |
107 |
} |
108 |
} |
109 |
|
110 |
sub show_directions { |
111 |
return |
112 |
join('', |
113 |
map { |
114 |
substr($step_name[$_],0,1) |
115 |
} @directions |
116 |
) |
117 |
; |
118 |
} |
119 |
|
120 |
sub shape { |
121 |
|
122 |
my ($x,$y) = @_; |
123 |
|
124 |
$pos = $y * $ll * 2 + $x * 2; |
125 |
|
126 |
warn "<<< shape from $x,$y pos: $pos\n"; |
127 |
@trace = ($unknown) x ( $#board + 1 ); |
128 |
@directions = (); |
129 |
trace; |
130 |
|
131 |
my $len = 0; |
132 |
|
133 |
while( 1 ) { |
134 |
|
135 |
my $next_pos = $pos + $move_by[ $step ]; |
136 |
warn "# pos: $pos next_pos: $next_pos step: $step $step_name[$step] trace: ",show_directions,"\n"; |
137 |
|
138 |
if ( $trace[ $next_pos ] ne $unknown ) { |
139 |
warn "position $next_pos re-visited, exiting\n"; |
140 |
last; |
141 |
} elsif ( $board[ $next_pos ] =~ $ok_path ) { |
142 |
warn "OK next_pos = $next_pos b($board[$next_pos]) t($trace[$next_pos])\n"; |
143 |
move; |
144 |
$len++; |
145 |
can_turn( $step + 1 ); |
146 |
} else { |
147 |
warn "find line continuation from $step $step_name[$step]...\n"; |
148 |
can_turn( $step - 1 ) || can_turn( $step + 1 ) || die "can't find new direction"; |
149 |
} |
150 |
warn draw( @trace ); |
151 |
|
152 |
if ( $debug ) { |
153 |
print "WAIT> press enter | ",show_directions; my $foo = <STDIN>; |
154 |
} |
155 |
} |
156 |
|
157 |
push @found, { x => $x, y => $y, len => $len, directions => show_directions }; |
158 |
|
159 |
warn ">>> ended at $pos, line length: $len, directions traversed: ",show_directions,"\n"; |
160 |
print "WAIT> press enter"; my $foo = <STDIN>; |
161 |
|
162 |
return $len; |
163 |
} |
164 |
|
165 |
my $shapes = '0,0 1,0 0,3'; |
166 |
|
167 |
foreach my $start ( split(/\s/,$shapes) ) { |
168 |
my $len = shape( split(/,/,$start) ); |
169 |
warn "## $start has $len elements\n"; |
170 |
} |
171 |
|
172 |
print ">>> RESULTS:\n"; |
173 |
foreach my $r ( @found ) { |
174 |
printf "%2d,%-2d len: %-4d directions: %s\n", $r->{x}, $r->{y}, $r->{len}, $r->{directions}; |
175 |
} |