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package Graph::HeapElem;
use strict;
use vars qw($VERSION @ISA);
use Heap::Elem;
require Exporter;
@ISA = qw(Exporter Heap::Elem);
$VERSION = 0.01;
=head1 NAME
Graph::HeapElem - internal use only
=head1 DESCRIPTION
B<INTERNAL USE ONLY> for the Graph module
=head1 COPYRIGHT
Copyright 1999, O'Reilly & Associates.
This code is distributed under the same copyright terms as Perl itself.
=cut
# Preloaded methods go here.
sub new {
my $class = shift;
$class = ref($class) || $class;
# two slot array, 0 for the vertex, 1 for use by Heap
my $self = [ [ @_ ], undef ];
return bless $self, $class;
}
# get or set vertex slot
sub vertex {
my $self = shift;
@_ ? ($self->[0]->[0] = shift) : $self->[0]->[0];
}
# get or set weight slot
sub weight {
my $self = shift;
@_ ?
($self->[0]->[1]->{ $self->vertex } = shift) :
$self->[0]->[1]->{ $self->vertex };
}
# get or set parent slot
sub parent {
my $self = shift;
@_ ?
($self->[0]->[2]->{ $self->vertex } = shift) :
$self->[0]->[2]->{ $self->vertex };
}
# get or set heap slot
sub heap {
my $self = shift;
@_ ? ($self->[1] = shift) : $self->[1];
}
# compare two vertices
sub cmp {
my ($u, $v) = @_;
my ($uw, $vw) = ( $u->weight, $v->weight );
if ( defined $uw ) {
return defined $vw ? $uw <=> $vw : -1;
} else {
return defined $vw ? 1 : 0;
}
}
1;
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