Coding Towards The Answer, Part 11

Traversing The Tree …

Coding Towards The Answer, Part 10

3 main methods for Tree Traversal using DFS (Depth-First Search / Traversal):

In order Traversal (left, root, right)
Preorder Traversal (root, left, right)
Postorder Traversal (left, right, root)

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

def inorderTraversal(root):
    answer = []
    inorderTraversalUtil(root, answer)
    return answer

def inorderTraversalUtil(root, answer):
    if root is None:
        return

    inorderTraversalUtil(root.left, answer)
    answer.append(root.val)
    inorderTraversalUtil(root.right, answer)
    return

def preorderTraversal(root):
    answer = []
    preorderTraversalUtil(root, answer)
    return answer

def preorderTraversalUtil(root, answer):
    if root is None:
        return 

    answer.append(root.val)
    preorderTraversalUtil(root.left, answer)
    preorderTraversalUtil(root.right, answer)
    return

def postorderTraversal(root):
    answer = []
    postorderTraversalUtil(root, answer)
    return answer

def…