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#!/usr/bin/perl -w |
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|
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# symmetry.pl |
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# |
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# 08/26/07 02:40:37 CEST Dobrica Pavlinusic <dpavlin@rot13.org> |
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|
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use strict; |
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|
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my $board = << '_BOARD_'; |
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+-+-+-+-+-+-+-+-+ |
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| | |o| | | |
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+ + +-+ +-+ | |
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|o| | o | o | |
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+ + +-+ +-+ | |
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| | o | | | |
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+-+-+ +-+-+-+-+ |
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| | |o| | |
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+-+ + +-+-+ +-+ |
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| |o| |o|o|o|o| |
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+ + +-+-+-+-+ +-+ |
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|o| | | | |
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+ +-+-+-+-+-+-+-+ |
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| | o | |
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+-+-+-+-+-+-+-+-+ |
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| o | o | |
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+-+-+-+-+-+-+-+-+ |
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_BOARD_ |
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|
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my $debug = shift @ARGV || 0; |
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|
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my @board = map { split(//) } split(/\n/, $board); |
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my @trace; |
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my @visited = (' ') x ($#board + 1); |
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|
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# line length |
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my $ll = 8 * 2 + 1; |
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|
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my @step_name = ( qw/right down left up/ ); |
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my @move_by = ( 1, $ll, -1, -$ll ); |
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my $step = 0; # right |
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|
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# offset 0, top-left corner |
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my $pos = 0; |
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|
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# unknown trace position |
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my $unknown = ' '; |
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|
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# path traversed |
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my @directions; |
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|
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my @shapes_found; |
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|
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my @shapes_start = ( '0,0' ); #( qw/0,0 1,0 0,3/ ); |
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|
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sub draw { |
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my $o = 0; |
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my $out = "\n " . join('', |
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('0 1 2 3 4 5 6 7 8 | ') x 3 |
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) . "\n"; |
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while ( $o < $#board ) { |
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my $l = '|'; |
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if ( $o % ($ll*2) == 0) { |
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my $y = int($o / ($ll*2)); |
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$out .= "$y "; |
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$l = $y; |
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} else { |
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$out .= " "; |
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} |
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|
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$out .= join('', @board[ $o .. $o + $ll - 1 ]); |
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$out .= " $l "; |
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$out .= join('', @trace[ $o .. $o + $ll - 1 ]); |
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$out .= " $l "; |
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$out .= join('', @visited[ $o .. $o + $ll - 1 ]); |
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$out .= " $l\n"; |
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$o += $ll; |
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} |
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|
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$out .= "\n"; |
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|
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return $out; |
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} |
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|
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sub trace { |
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warn "## trace $pos\n"; |
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$trace[ $pos ] = $board[ $pos ]; |
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$visited[$pos]++; |
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} |
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|
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sub x_y { |
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my $p = shift; |
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|
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$p ||= $pos; |
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|
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my $y = int($p / ($ll*2)); |
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my $x = int(($p % $ll) / 2); |
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|
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warn "## x_y($p) -> $x,$y\n"; |
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|
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# return ($x,$y) if wantarray; |
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return "$x,$y"; |
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} |
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|
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sub move { |
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$pos += $move_by[ $step ]; |
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trace; |
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$pos += $move_by[ $step ]; |
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trace; |
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push @directions, $step; |
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warn "move $step $step_name[$step] to ", x_y, "\n"; |
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} |
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|
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sub follow { |
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$step = shift; |
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$step %= 4; |
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warn "follow $step $step_name[$step]\n"; |
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} |
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|
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my $ok_path = qr/[\|\-]/; |
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|
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my @corners; |
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my $corners_usage; |
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|
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sub can_turn { |
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my $try_step = shift; |
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die "no step?" unless defined $try_step; |
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|
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$try_step %= 4; |
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|
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my $turn_pos = $pos + $move_by[$try_step]; |
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|
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my $old = $trace[ $turn_pos ]; |
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$trace[ $turn_pos ] = '?'; |
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$trace[ $pos ] = '*'; |
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warn "TEST ", x_y($turn_pos), "\n",draw; |
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$trace[ $turn_pos ] = $old; |
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|
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if ( $board[ $turn_pos ] =~ $ok_path ) { |
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my $xy = x_y($pos); |
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warn "OK can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos]) from $xy\n"; |
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$step = $try_step; |
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push @corners, $xy; |
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$corners_usage->{$xy}++; |
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return 1; |
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} else { |
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warn "NOPE can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos])\n"; |
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return 0; |
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} |
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} |
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|
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sub show_directions { |
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return |
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join('', |
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map { |
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substr($step_name[$_],0,1) |
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} @directions |
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) |
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; |
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} |
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|
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sub shape { |
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|
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my ($x,$y) = @_; |
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|
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$pos = $y * $ll * 2 + $x * 2; |
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|
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@trace = ($unknown) x ( $#board + 1 ); |
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@directions = (); |
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@corners = (); |
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trace; |
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|
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my $len = 0; |
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$step = 0; |
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|
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my $usage = $corners_usage->{"$x,$y"} || 0; |
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|
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warn "<<< shape from $x,$y [usage: $usage] pos: $pos\n"; |
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|
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if ( $usage > 4 ) { |
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warn "SKIPPED, usage > 4\n"; |
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return; |
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} |
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|
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while( 1 ) { |
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|
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my $next_pos = $pos + $move_by[ $step ]; |
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warn "# pos: $pos next_pos: $next_pos step: $step $step_name[$step] trace: ",show_directions,"\n"; |
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|
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if ( $trace[ $next_pos ] ne $unknown ) { |
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warn "position $next_pos re-visited, exiting\n"; |
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last; |
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} elsif ( $board[ $next_pos ] =~ $ok_path ) { |
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warn "OK next_pos = $next_pos b($board[$next_pos]) t($trace[$next_pos])\n"; |
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move; |
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$len++; |
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can_turn( $step + 1 ); |
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} else { |
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warn "find line continuation from $step $step_name[$step]...\n"; |
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can_turn( $step - 1 ) || can_turn( $step + 1 ) || die "can't find new direction"; |
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} |
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warn draw; |
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|
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if ( $debug ) { |
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print "WAIT> press enter | ",show_directions; my $foo = <STDIN>; |
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} |
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} |
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|
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push @shapes_found, { x => $x, y => $y, len => $len, directions => show_directions }; |
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|
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warn "### corners: ",join(' ', map { $_ . " [" . $corners_usage->{$_} . "]" } @corners),"\n"; |
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warn ">>> ended at $pos, line length: $len, directions traversed: ",show_directions,"\n"; |
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|
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foreach my $c ( @corners ) { |
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if ( ! grep( /\Q$c\E/, @shapes_start ) ) { |
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warn "INFO: added corner $c as shape start\n"; |
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push @shapes_start, $c; |
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} |
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} |
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|
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print "WAIT> press enter"; my $foo = <STDIN>; |
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|
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return $len; |
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} |
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|
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foreach my $start ( @shapes_start ) { |
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my ($x,$y) = split(/,/,$start); |
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if ( $x < 8 && $y < 8 ) { |
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my $len = shape( split(/,/,$start) ); |
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warn "## $start has $len elements\n"; |
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} else { |
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warn "SKIPPED $start\n"; |
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} |
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} |
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|
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print ">>> RESULTS:\n"; |
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foreach my $r ( @shapes_found ) { |
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printf "%2d,%-2d len: %-4d directions: %s\n", $r->{x}, $r->{y}, $r->{len}, $r->{directions}; |
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} |