package DAG;
use strict;
use warnings;
use Graph::Directed;
use Carp;
use base 'Graph::Directed';
sub new {
my ( $self, %args ) = @_;
$args{multiedged} = 1;
my $obj = $self->SUPER::new(%args);
return $obj;
}
sub set_parents {
my ( $self, $p1, $p2, $c, $checks ) = @_;
$checks ||=1;
if ( ( $self->in_degree($c) || 0) > 0) {
croak "already has parents";
}
$self->add_edge_by_id($p1, $c, 1);
$self->add_edge_by_id($p2, $c, 2);
if ($checks && !$self->is_dag()) {
$self->delete_edge_by_id($p1, $c, 1);
$self->delete_edge_by_id($p2, $c, 2);
croak 'Not a DAG anymore';
}
return $self;
}
####
...
sub is_ancestor {
my ( $self, $v1, $v2 ) = @_;
for my $child ( $self->get_successors($v1) ) {
return 1 if $child eq $v2;
}
for my $child ( $self->get_successors($v1) ) {
my $found = $self->is_ancestor( $child, $v2 );
return 1 if $found;
}
return 0;
}
sub set_parents {
my ( $self, $p1, $p2, $c, $checks ) = @_;
$checks ||=1;
if ( ( $self->in_degree($c) || 0) > 0) {
croak "already has parents";
}
$self->add_edge_by_id($p1, $c, 1);
if ($checks && $self->is_ancestor($c, $p1)) {
$self->delete_edge_by_id($p1, $c, 1);
croak 'Not a DAG anymore';
}
$self->add_edge_by_id($p2, $c, 2);
if ($checks && $p1 ne $p2 && $self->is_ancestor($c, $p2)) {
$self->delete_edge_by_id($p2, $c, 2);
croak 'Not a DAG anymore';
}
return $self;
}
##
##
P1 --+
+--> Child
P2 --+