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lib/Algorithm/DLX.pm  view on Meta::CPAN

    my ($class, $row, $col) = @_;
    my $self = {
        row     => $row,
        col     => $col,
        left    => undef,
        right   => undef,
        up      => undef,
        down    => undef,
        column  => undef,
    };
    bless $self, $class;
    return $self;
}

# Column structure for DLX
package DLX::Column;
use base 'DLX::Node';
sub new {
    my ($class, $col) = @_;
    my $self = $class->SUPER::new(undef, $col);
    $self->{size}   = 0;
    $self->{name}   = $col;
    $self->{column} = $self;
    bless $self, $class;
    return $self;
}

# Main DLX package
package Algorithm::DLX;

sub new {
    my ($class) = @_;
    my $self = {
        header      => DLX::Column->new('header'),
        solution    => [],
        solutions   => [],
    };

    # Initialize header links
    $self->{header}->{left}     = $self->{header};
    $self->{header}->{right}    = $self->{header};
    bless $self, $class;

    return $self;
}

sub add_column {
    my ($self, $col_name) = @_;
    my $col = DLX::Column->new($col_name);

    $col->{left}    = $self->{header}->{left};
    $col->{right}   = $self->{header};