Implement function to make grid edges.

lib/Algorithm/Simpath/GridMaker.pm

@@ -0,0 +1,58 @@
+package Algorithm::Simpath::GridMaker;
+use strict;
+use warnings;
+use Exporter qw(import);
+our @EXPORT_OK = qw(create_edges);
+
+sub create_edges($$) {
+    my ($cols, $rows) = @_;
+    my $width  = $cols + 1;
+    my $height = $rows + 1;
+
+    my @edges;
+    for my $n (0 .. $width + $height - 1) {
+        for my $x (0 .. $n) {
+            my $y = $n - $x;
+            $x < $width && $y < $height or next;
+            push @edges, ["$x,$y", ($x + 1) . ",$y"] if $x + 1 < $width;
+            push @edges, ["$x,$y", "$x," . ($y + 1)] if $y + 1 < $height;
+        }
+    }
+
+    \@edges;
+}
+
+1;
+__END__
+
+=head1 NAME
+
+Algorithm::Simpath::GridMaker -
+
+=head1 SYNOPSIS
+
+  use Algorithm::Simpath;
+  use Algorithm::Simpath::GridMaker;
+
+  my $edges = Algorithm::Simpath::GridMaker::create_edges(5, 5);
+  my $zdd = solve(
+      start => '0,0', goal  => '5,5', edges => $edges
+  );
+  print $zdd->count, "\n"; # 1262816
+
+=head1 DESCRIPTION
+
+Algorithm::Simpath::GridMaker is
+
+=head1 AUTHOR
+
+hiratara E<lt>hiratara {at} cpan.orgE<gt>
+
+=head1 SEE ALSO
+
+=head1 LICENSE
+
+This library is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself.
+
+=cut

t/grid_maker.t

@@ -0,0 +1,13 @@
+use strict;
+use warnings;
+use Test::More;
+use Algorithm::Simpath;
+use Algorithm::Simpath::GridMaker;
+
+my $edges = Algorithm::Simpath::GridMaker::create_edges(5, 5);
+my $zdd = solve(
+    start => '0,0', goal  => '5,5', edges => $edges,
+);
+is $zdd->count, 1262816;
+
+done_testing;