Meta (formerly Facebook) is renowned for its rigorous, systematic interview process, especially the Virtual Onsite (VO) rounds—a critical gateway to landing an offer. As many candidates note, “The difficulty is high, but it sharpens your thinking.” Drawing from real interview experiences, this article shares high-frequency Meta VO questions and insights to help you master the format and prepare efficiently.
Meta VO Interview Process
- Submitting a resume: It may take three days to three months (the well-known long timeline) from submitting a resume to receiving an interview notice. However, it’s worth noting that if a position is closed, there will be a cooling-off period during which you cannot apply for the same type of position again.
- Phone screening (Optional): The HR representative will call you to confirm your visa status, professional background, and interview time. At this stage, you should appear confident and approachable, letting the HR representative sense your enthusiasm and sincerity for the job. Typically, there won’t be a technical interview at this stage!
- Online Assessment (OA) / Technical Phone Interview: Moderate difficulty, complete 4 questions within 70 minutes. Usually, HR will send you the OA link on the same day or the next day, which is valid for one week. Start solving problems! Alternatively, you may receive an interview invitation (phone interview). Phone Interview: An engineer will chat with you, ask you two questions that may be completely unrelated, or one question, and then ask follow-up questions. Whether it’s an intern or a new graduate, the difficulty level of the algorithm interview is the same.
- Virtual Onsite (VO): Generally, HR will arrange Virtual Onsite two weeks later, which may include three rounds of coding and one round of behavioral questioning, or one round of system design. Since 2023, it is now possible to negotiate with HR to complete the interview over two days (previously, it was completed within one day).
Meta VO Real Interview Questions
Now that we’ve covered the overall interview process at Meta, let’s take a look at the interview questions for Meta VO.
1. Binary Tree Dual-Sided View Traversal
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 toright side of the tree, and return the values of the nodes you can see ordered from top to bottom.
# Binary Tree:
# ----> 1
# / \
# ----> 2 3 6 5 4 1
# / \
# ----> 2 3 5 <---
# Answer: [5, 2, 1, 3, 5]A frequently examined Meta VO question involves finding the first visible node when looking from the bottom-up on the left side and top-down on the right side of a binary tree. The approach is to maintain two dictionaries: one recording the first encountered node at each depth level (leftmost nodes), and the other recording the last encountered node at each depth level (rightmost nodes). The solution is then derived by combining these two dictionary structures.
2. Vertical Order Traversal of a Binary Tree
Given the root of a binary tree containing integers, print each column from left to right, and within each column print the values from top to bottom.
6 / \ 3 4 / \ / \ 5 1 0 / \ 2 / \ 9 8 \ 7 Output: 5 9 3 2 6 1 7 4 8 0
Clarify Question
First, confirm whether the input includes an empty tree scenario, as this is a common edge case in binary tree problems. Second, clarify the expected output format: whether to return a list structure or simply output the results directly during processing.
Approach:
We need to output the value of each node from left to right and top to bottom. Clearly, we should group nodes by their column index, ensuring that within each column, nodes are visited from top to bottom.
For this purpose, the Breadth-First Search (BFS) algorithm is particularly suitable. Given the uncertain range of column indices, we can assume the column index of the root node to be 0. When moving to a left child node, the column index decreases by 1; when moving to a right child node, it increases by 1. After completing the BFS traversal, we iterate through the hashmap once to find the minimum and maximum column indices. Then, using a nested loop, we generate the final output based on these column indices.
This approach ensures an organized traversal of the binary tree, producing a sorted list of node values according to their column and row positions.
3. Meta VO System Design
The task is to design a Ticketmaster system.
we wanted to follow Alex Xu’s approach, but the guy said we shouldn’t waste time on back-of-the-envelope calculations or worry about distributed systems. He suggested focusing on mapping out the user flow and creating a diagram that includes all the components.
Requirement:
- How to handle scenarios where a large number of people are trying to buy tickets within a short period of time.
- How to implement a timeout for the ticket purchasing interface, and how to handle cases where the user does not complete the payment within the specified time.
- What actions to take when all tickets have been sold out.
- How to ensure that a person who has completed the payment definitely gets their ticket.
- How to implement a waitlist, so that if any ticket holders cancel their tickets, those on the waitlist are notified in order of their position on the list.
Candidate Tips from Successful Interviews
- Coding: Prioritize Clarity Over Speed
Explain your thought process aloud as you code. Highlight how you’re handling edge cases (e.g., empty inputs, cycles in graphs) to showcase systematic thinking. - System Design: Structure Before Diagrams
Start by clarifying requirements (e.g., user count, latency goals), then break down the system into modules (e.g., client layer, conflict resolution service). Present the architecture diagram last to solidify your logic. - Behavioral Interviews: Lead with Impactful Stories
Use the STAR method to illustrate how you’ve contributed to team success. For example, detail a project where you resolved a critical bug or improved system efficiency, emphasizing your role and the outcome. - English Proficiency: Structure Over Perfect Fluency
Prepare bullet points for common behavioral questions (e.g., “Tell me about a time you failed”) to ensure your narrative flows logically. Practice articulating technical concepts in simple terms.
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