[Tutor] Most efficient representation of a tree?

[VanL]

Hello,

What would be the most efficient representation of a tree? 
In this tree, each node could have an arbitrary number of children.
I also wanted to be able to order the children so I can traverse the
trees in different ways (preorder, postorder, etc).  Anyway, at least a
leftmost-child, right-sibling ordering.

I was considering two options:

1. A modification of Guido's adjacency-list implementation of a graph
(see http://www.python.org/doc/essays/graphs.html).  After all, this
sort of tree is just special case sparse graph.

2. A node class with a parent link and a list of links to each child --
essentially a generalization of the linked list class that I posted here
a month ago.

Any other options?

Does anyone have any idea how these would compare in terms of speed and
execution resources?

Thanks,

VanL