Source: 📖 Problem Solving with Algorithms and Data Structures using Python 7.7
Date: 2021-12-26
Postorder tree traversal is when a binary tree is traversed by first recursively doing a postorder tree traversal on the left child node, then on the right child node, and then finally visiting the root node.Preorder tree traversal is when a binary tree is traversed by first visiting the root node, then recursively doing a preorder traversal of the left node and then the right node.
def postorder_traversal(tree):
if tree:
postorder_traversal(tree.left_child)
postorder_traversal(tree.right_child)
print(tree.key)
First we check that the tree is not None. Next we recursively run the function on the left sub-tree, then the right sub-tree, before finally visiting the root node and printing out its value.