Lowest Common Ancestor of a Binary Tree — DSA Technical Interview Questions & Answers

Lowest Common Ancestor of a Binary Tree

Lowest Common Ancestor of a Binary Tree

  • Lowest Common Ancestor of a Binary Tree is a DSA topic. In plain words you use it for folder on disk in a file explorer. Don’t start with a slogan — start with that picture.
  • Smallest example: left < root < right. Type it, run it, and say what you see. If you can do that from memory, you know Lowest Common Ancestor of a Binary Tree.
  • From the example next to this theory: Lowest Common Ancestor of a Binary Tree — inorder walks left → node → right (sorted order for a BST).
  • Trap: unbalanced BST becoming a list. Fix that before you talk about advanced DSA.
  • Viva: what is Lowest Common Ancestor of a Binary Tree? Then show left < root < right. Then name the trap.

Technical Interview Tip: What is Lowest Common Ancestor of a Binary Tree? Show this: left < root < right. Trap: unbalanced BST becoming a list.

Code Examples for Lowest Common Ancestor of a Binary Tree

Lowest Common Ancestor of a Binary Tree — working example

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

def inorder(n):
    if not n:
        return []
    return inorder(n.left) + [n.val] + inorder(n.right)

root = Node(2, Node(1), Node(3))
print(inorder(root))

Lowest Common Ancestor of a Binary Tree — inorder walks left → node → right (sorted order for a BST).

How to Explain Lowest Common Ancestor of a Binary Tree to an Interviewer

What is Lowest Common Ancestor of a Binary Tree?

Used for folder on disk a file explorer Not just the heading

Give one small example of Lowest Common Ancestor of a Binary Tree.

left < root < right Lowest Common Ancestor of a Binary Tree — inorder walks left → node → right (sorted order for a BST)

What mistake do beginners make with Lowest Common Ancestor of a Binary Tree?

unbalanced BST becoming a list Show the fix

Where do you use Lowest Common Ancestor of a Binary Tree?

a file explorer folder on disk