Meta Interview Questions — Page 40

Meta·Machine Learning Engineer·Technical Phone Screen

Apr 2026

Meta MLE coding round, just one algorithmic problem but it was a tricky greedy one that I hadn't thought about in a while. Felt okay about my solution but not confident I nailed the optimal approach right away.

A car starts at position 0 and needs to reach a destination `target` miles away. Gas stations are scattered along the route, each with a known position and fuel amount. The car begins with `startFuel` liters and consumes 1 liter per mile. You can stop at any station to take all its fuel. What is the minimum number of refueling stops needed to reach the destination, or -1 if it's impossible?

“I knew this was a greedy problem pretty quickly but fumbled the implementation for a bit.”

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Meta·Product Manager·Hiring Manager Screen

Apr 2026

Went through a PM interview at Meta, just the one question about achievements. Not much to go on but it's a classic they love to dig into.

What is your proudest achievement as a PM?

“I had an answer prepped but the moment they asked it I second-guessed whether my example was actually impressive enough for Meta.”

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Meta·Product Manager·Onsite - Product Sense / Strategy

Apr 2026

Meta PM interview with a product design question that deliberately steered away from anything Facebook-related. Short prompt, but the open-endedness made it trickier than it sounds.

Design a product that solves a problem in the parking space. The solution cannot be related to Facebook or Meta's existing products.

“The constraint about not using Facebook felt weirdly specific and I spent the first minute just sitting with it.”

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Meta·Machine Learning Engineer·Onsite - Coding / Algorithms

Apr 2026

Did a coding round for an MLE role at Meta, four problems back to back. The first two were classic CS fundamentals but the last one had a constraint that made me rethink my whole approach mid-solve. Mixed feelings about how it went.

Given the head of a singly linked list that may contain a cycle, return the node where the cycle begins, or null if there is no cycle. You must use O(1) extra space.
In a BST where each node has left, right, and parent pointers, return the in-order successor of a given node. Return null if none exists.
Design a class for an n×n tic-tac-toe board. It should support a move operation that places a player's mark and returns whether that player has won. Each move should run in close to O(1) time.
Given an n×n binary grid where 1s are land and 0s are water, you can flip at most one 0 to a 1. Return the maximum possible island size after the flip. The grid can be up to 500x500, so near-quadratic extra work may time out.

“Floyd's algorithm, fine.”

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Meta·Software Engineer·Technical Phone Screen

Apr 2026

Meta coding screen, path manipulation problem that looks easy until you actually sit down and think about edge cases. Walked away feeling okay about it but not great.

Given two absolute directory paths, return the shortest relative path string that would navigate from the first to the second, as if passed to the `cd` command.

“I started by splitting both paths on '/' and finding the common prefix, which is the right instinct.”

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Meta·Data Scientist·Technical Phone Screen

Apr 2026

A technical screen for a DS role at Meta that went deep fast. The whole thing was basically one sprawling experiment design question about fake account removal, and they wanted specifics on everything from cluster construction to quasi-experimental fallbacks. Felt like a take-home crammed into a live session.

Your team is removing detected fake accounts and wants to measure the causal impact on real users' experience. Design a full experiment plan that handles network interference and product trade-offs, covering randomization strategy, metrics, power calculations, spillover diagnostics, noncompliance, rollout safety, and quasi-experimental fallbacks.
Between user-level, ego-network cluster, and geography-level randomization, which would you choose for this fake account removal experiment and why? How would you build clusters to limit cross-treatment contamination without killing statistical power?
What primary and guardrail metrics would you define for this experiment? Be specific about metric formulas, time windows, and whether they are exposure-based or calendar-based.
Walk through a sample size calculation for detecting a 0.5% relative change in comments per view, assuming a baseline of 0.12, overdispersion, and an intra-cluster correlation of 0.02.
Propose two specific tests to detect and quantify spillover effects in this experiment. What would the null hypothesis look like for each?
Detection of fake accounts is imperfect. How would you handle noncompliance and misclassification when estimating the treatment effect? Walk through an instrumental variable or difference-in-differences approach.
How would you design a staged rollout with kill-switch criteria? How do you prevent label leakage through feeds or notifications during the experiment?
If randomization is not feasible in certain markets, what quasi-experimental approach would you use as a backup? What specific covariates from logs would you need, and what product recommendation would you make if engagement drops short-term but abuse reports fall significantly?

“This was essentially seven questions in a trenchcoat.”

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Meta·Software Engineer·Technical Phone Screen

Apr 2026

Meta SWE coding round, just one question about cloning a linked list with a random pointer. Short session, not a lot of context shared about how it went.

Given a linked list where each node has a next pointer and a random pointer that can point to any node in the list (or null), return a deep copy of the list.

“Classic problem but the random pointer is what trips people up.”

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Meta·Software Engineer·Technical Phone Screen

Apr 2026

Short technical screen for a Data Engineer role at Meta, 15-minute coding format. Pretty focused and fast-paced, basically write a small Python function and talk through your thinking.

Before you start coding, what clarifying questions would you ask the interviewer about the problem?
What edge cases does your solution need to handle, and how does your code address each one?
Walk through your code and explain the formatting and readability choices you made.
What is the time and space complexity of your solution, and what would a minimal test plan look like?

“I always freeze a little here because asking too many questions feels like stalling.”

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Meta·Software Engineer·Onsite - Multi Round

Apr 2026

Meta SWE loop that got complicated when the interview track shifted partway through. Had to rethink prep, figure out how to talk to the recruiter about it, and hope the earlier evals didn't just get thrown out.

Walk through a situation where your interview process changed direction mid-loop. How did you adjust your preparation, communicate with the recruiter and panel, and make sure your earlier evaluations were still counted? What would you change to make the transition smoother?

“This one is deceptively hard to answer well because it's not just about adaptability, it's also about process navigation and managing people.”

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Meta·Software Engineer·Technical Phone Screen

Apr 2026

Meta SWE coding round, one question on graph cloning. Pretty focused session, no fluff.

Given the starting node of an undirected graph where each node holds an integer value and a list of neighbors, write a function that returns a deep copy of the entire graph.

“The adjacency list representation tripped me up for a second because you have to track visited nodes or you'll loop forever on cycles.”

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