Most efficient way of creating tree from adjacency list

Question

I have an adjacency list of objects (rows loaded from SQL database with the key and it\'s parent key) that I need to use to build an unordered tree. It\'s guaranteed to not

Answer 1

1. Put the nodes into a sorted list or dictionary.

2. Scan that list, pick up each node, find its parent node in the same list (binary search or dictionary lookup), add it to the Children collection of the parent node.

There's no need for a Stack to put this into a tree.