view release on metacpan or  search on metacpan

Combinatorics.pm  view on Meta::CPAN

    return __contextualize($iter);
}

sub __permutations_heap {
    my ($data) = @_;
    __check_params($data, 0);

    return __contextualize(__once_iter()) if @$data == 0;

    my @a = 0..(@$data-1);
    my @c = (0) x (@$data+1); # yeah, there's an spurious $c[0] to make the notation coincide
    my $iter = Algorithm::Combinatorics::Iterator->new(sub {
        __next_permutation_heap(\@a, \@c) == -1 ? undef : [ @{$data}[@a] ];
    }, [ @{$data}[@a] ]);

    return __contextualize($iter);
}


sub derangements {
    my ($data) = @_;