Meta Software Engineer Interview Questions (2026)
Meta's software engineer loop is known for its pace: coding rounds typically expect you to solve two medium problems in 35–40 minutes with clean, working code. The loop also includes a system design round ("Ninja"/product architecture for senior levels) and a behavioral round Meta calls "Jedi," focused on conflict, impact, and how you operate.
Speed matters at Meta, but not at the cost of correctness — interviewers want you to talk and type at the same time, get to a working solution quickly, then optimize. Edge cases and clean code are explicitly scored. Practicing for throughput, not just difficulty, is the differentiator.
The questions below reflect Meta's coding and behavioral patterns. The behavioral round is weighted heavily for level calibration, so prepare concrete stories about driving impact and navigating disagreement, not just technical wins.
Meta Software Engineer Interview Questions & How to Answer Them
1. Validate a binary search tree.
Approach: Recurse with min/max bounds rather than just comparing parent-child. State why the naive parent-child check fails. Meta rewards getting the correct invariant fast and stating the edge cases (duplicates, single node).
2. Merge k sorted lists.
Approach: Min-heap of k heads (O(N log k)) or divide-and-conquer pairwise merge. Code it cleanly and quickly — this is a common first problem and interviewers watch how fast you reach working code.
3. Subarray sum equals k.
Approach: Prefix-sum + hash map of counts in O(n). Explain why the running-sum-difference trick works. A frequent Meta problem that separates candidates who pattern-match prefix sums from those who brute force.
4. Right side view of a binary tree.
Approach: Level-order BFS taking the last node per level, or DFS tracking depth. Both O(n). Narrate while coding — Meta explicitly values talking through the solution as you type.
5. Random pick with weight.
Approach: Prefix sums + binary search on a random draw. Walk the probability reasoning. A Meta favorite because it tests whether you can map a probability requirement onto a clean data structure.
6. Design Facebook's News Feed.
Approach: Clarify scale and ranking scope. Discuss fan-out-on-write vs fan-out-on-read, the celebrity problem, caching, and ranking as a separable service. Meta's design round wants product-aware architecture, not just plumbing.
7. Add two numbers represented as linked lists.
Approach: Walk both lists with a carry, build the result node by node. O(max(m,n)). Handle the trailing carry edge case — interviewers check it deliberately.
8. Tell me about a time you disagreed with your manager or a teammate.
Approach: STAR. Meta's behavioral round screens for handling conflict directly and constructively, plus the impact of the resolution. Choose a story where you disagreed, engaged respectfully, and drove a concrete outcome.
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