Rad Hires stores nested hiring workflows as a tree. Each node has a name and an ordered list of child nodes. Write a function that traverses the tree efficiently and returns the full path of every node in preorder, where a parent appears before all of its descendants.
The tree may be much deeper than Python's recursion limit, so your implementation must use an explicit stack rather than recursive function calls.
Input root is a dictionary with the structure {"name": string, "children": list[dict]}. Every child follows the same structure, and the tree contains no cycles. Return a list of strings. Each string joins node names from the root to that node with /.
Child order must be preserved. The input contains at least one node.
/def flatten_hierarchy(root):