I recently came across two new Meta interview questions, both centered around binary trees and BSTs. Below I’ll share the original problem statements, the reasoning process, and how CSOAHelp assistance made a big difference during the interview.

Question 1: Binary Tree Left and Right Sides View

Original Statement

Given a binary tree, imagine yourself standing on the left side of it, 
return the values of the nodes you can see ordered from bottom to top, 
then switch to right side of the tree, 
and return the values of the nodes you can see ordered from top to bottom.

Example
Binary Tree:

       1
     /   \
    2     3
   / \     \
  6   5     4

Output: [6, 2, 1, 3, 4]

Question 2: Longest Increasing Path in a BST

Original Statement

A Binary Search Tree (BST). Every node has an integer key. 
Each node's key is greater than all keys in its left subtree, 
and smaller than all keys in its right subtree.  

Find an integer representing the length of the longest strictly increasing path in the BST.  
The path does not have to be rooted; it can start at any node and end at any node.

Example
Input:

      4
     / \
    2   5
   / \    \
  1   3    6

Output: 3
(The longest increasing path can be [4,5,6] or [2,3,6].)

Solution Walkthrough

During the interview, the candidate started by clarifying edge cases:

• Should an empty tree return [] or 0?
• Are duplicate values allowed?
• Can the path in Question 2 go in any direction or only downward?

These clarifications immediately showed the interviewer strong communication skills.

For Question 1, the core approach was level-order BFS:

• At each level, record the first node for the left view.
• At each level, record the last node for the right view.
• Reverse the left view (bottom → top), keep the right view as is (top → bottom), then combine the results while avoiding duplication of the root.

For Question 2, the approach was DFS with recursion and a global maximum:

• From each node, explore child paths only if the next value is strictly greater.
• Track the longest path length across all nodes.
• Since the path can start anywhere, run DFS from every node, not just the root.

Complexity:

• Both problems run in O(n) time, where n = number of nodes.
• Space depends on tree height, worst-case O(n).

How CSOAHelp Made the Difference

Without guidance, candidates often make small but costly mistakes:

• In Question 1, forgetting to avoid duplicating the root node in the result.
• In Question 2, limiting the DFS to direct children instead of considering new paths starting at any node.

With CSOAHelp real-time assistance:

• Instructors highlight important clarifying questions early, making the candidate look professional.
• When stuck, they drop the right keywords — “BFS edge nodes,” “DFS + global max” — to get the thought process back on track.
• For follow-up questions, they prompt optimizations like idempotency or space reduction, giving the answer more depth.

The end result was not just working code, but a complete, structured, and confident explanation, which is exactly what interviewers are looking for.

🚀 If you’re preparing for Meta, Google, Amazon, or other top tech companies, and want to deliver consistent, high-quality answers under pressure, check out CSOAHelp.com. With targeted prep and live assistance, you’ll be ready to shine even in the toughest interviews.