Python Program to Implement Depth First Search Traversal using Post Order

This Python program explores Depth-First Search (DFS) traversal in a binary tree, specifically using the post-order technique. Post-order traversal follows the sequence: left subtree, right subtree, and then the root. This program demonstrates essential tree traversal methods and the practical use of post-order traversal in binary trees.

Problem Statement

The goal is to write a Python program that performs a depth-first search (DFS) traversal of a binary tree using the post-order technique. Post-order traversal is particularly useful for tasks such as deleting nodes or evaluating expressions within the tree.

Python Program to Implement Depth First Search Traversal using Post Order

class TreeNode:
    def __init__(self, data):
        self.data = data
        self.left = None
        self.right = None

def post_order_traversal(root):
    if root is not None:
        post_order_traversal(root.left)
        post_order_traversal(root.right)
        print(root.data, end=" ")

# Example usage
if __name__ == "__main__":
    # Creating a binary tree
    root = TreeNode(10)
    root.left = TreeNode(5)
    root.right = TreeNode(15)
    root.left.left = TreeNode(3)
    root.left.right = TreeNode(7)
    root.right.right = TreeNode(18)

    print("Post-order traversal:")
    post_order_traversal(root)

Input / Output