Following up on this a bit more...

I found that duplicates in each input array would cause problems, so I put in a check for this (above, in a previous post).

What I'm finding now, is that problems arise when the input arrays are totally unique. That is, an interection of all the arrays would yield no elements.

Consider this code:

#!/usr/bin/perl

use strict;
use warnings;

use Graph::Directed;

my @array1= ( 1, 2, 3, 4);
my @array2= ( 5, 6, 7, 8);
my @array3= ( 9, 10, 11, 12);


my $graph = Graph::Directed->new;
$graph->add_path(@array1);
$graph->add_path(@array2);
$graph->add_path(@array3);


my @ordered = $graph->toposort();
print "@ordered";
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Note that, for this example, I'm using numerals. However, the desired order is not alphabetical, ASCIIbetical, numerical, or anything similar. What's important is the order that the elements appear in the arrays.

The problem here, is that the vertices in this example are not strongly connected. So, rather than getting:
1 2 3 4 5 6 7 8 9 10 11 12

I get:
5 1 2 9 10 3 4 11 12 6 7 8

Is there a way have the topological sort expect unique arrays, with no connections, and weight them, based on the order they are received?

You see, sometimes the arrays will be connected, sometimes they won't... so I need a system that will account for both cases, without being explicitly told which is which.