I need to generate a node list for some network devices I manage and I need it to be in a hierarchical structure when I am done.

I have the following list that is generated where the fist item it the child and the second item is the parent:

b:a
c:a
d:b
e:c
f:c
[download]

And it needs to look like this when I am done:

   +-b--d
a -+
   +   +-e
   +-c-+
       +-f
[download]

I can parse out my input and basically generate the first list in an array or hash. But, what I am not sure of is how to generate the final data structure as I need to loop through the original list and come up with the hierarchy relationships. I have no idea how to store this either.

Any help with this would be appreciated.

2006-03-22 Retitled by planetscape, as per Monastery guidelines
Original title: 'a complex data structure'