44 lines
764 B
Perl
44 lines
764 B
Perl
use 5.20.0;
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use Digest::MD5 qw/ md5_hex /;
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use Math::Vector::Real;
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use List::AllUtils qw/ min max minmax /;
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my @directions = (
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[ 'U', V(0,-1) ],
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[ 'D', V(0,1) ],
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[ 'L', V(-1,0) ],
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[ 'R', V(1,0) ],
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);
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my $best_path;
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wander( 'bwnlcvfs', V(0,0) );
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say length($best_path) - 8;
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sub wander {
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my( $hash, $c ) = @_;
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my( $min,$max ) = minmax @$c;
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return if 0 > $min;
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return if 3 < $max;
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if( $c == V(3,3) ) {
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say $hash;
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if( length($hash) >= length($best_path) ) {
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$best_path = $hash;
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}
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return;
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}
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my @md5 = split '', md5_hex($hash), 5;
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my @d = grep { (shift @md5) =~ /[b-f]/ } @directions;
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for my $d ( @d ) {
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wander( $hash . $d->[0], $c + $d->[1] );
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}
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}
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