Data Structures for Coding Interviews in Python/

...

/

Pre-Order Traversal

Pre-Order Traversal

In this lesson, we will cover the traversal strategy, 'Pre-Order Traversal' in a Binary Search Tree, and its implementation it in Python

We'll cover the following...

Introduction #

In this traversal, the elements are traversed in “root-left-right” order. We first visit the root/parent node, then the left child, and then the right child. Here is a high-level description of the algorithm for Pre-Order traversal, starting from the root node:

  1. Visit the current node, i.e., print the value stored at the node

  2. Call the preOrderPrint() function on the left sub-tree of the ‘current Node’.

  3. Call the preOrderPrint() function on the right sub-tree of the ‘current Node’.

Implementation in Python

...
Press + to interact
main.py
BinarySearchTree.py
Node.py
from Node import Node
from BinarySearchTree import BinarySearchTree
def preOrderPrint(node):
    if node is not None:
        print(node.val)
        preOrderPrint(node.leftChild)
        preOrderPrint(node.rightChild)
BST = BinarySearchTree(6)
BST.insert(4)
BST.insert(9)
BST.insert(5)
BST.insert(2)
BST.insert(8)
BST.insert(12)
preOrderPrint(BST.root)
...
Access this course and 1400+ top-rated courses and projects.