Software Engineer interview
at Meta.

Tell-me-about-a-time stories on ownership, conflict, and impact — scored against this company's real values.

1. 01 Tell me about a time you embodied 'Move Fast' to ship a feature, and how you balanced speed against reliability.
2. 02 Describe a project you owned end-to-end where you were responsible for both the approach and the outcome.
3. 03 Tell me about a time you received difficult feedback on your code or design and how you responded.
4. 04 Describe a time you disagreed with a teammate on a technical approach and how you resolved it.

The hard screen for the craft itself — talked through out loud, not whiteboarded in your head.

1. 01 Given a binary tree, return its vertical order traversal of node values, grouping nodes by column.
2. 02 Implement a function that validates whether a string of parentheses, brackets, and braces is balanced, then extend it to return the longest valid substring.
3. 03 Merge a list of overlapping intervals and then support efficiently inserting a new interval into the merged set.
4. 04 Given a stream of numbers, design a data structure that returns the running median in better than O(n) per query.

Open-ended design of the systems this company actually runs, with the interviewer probing your tradeoffs.

1. 01 Design Facebook's News Feed, covering feed generation, ranking, and fan-out for users with millions of followers.
2. 02 Design Instagram, including media upload, storage, and the feed serving path at billions-of-users scale.
3. 03 Design Facebook Live comments so that comments appear in near real time for millions of concurrent viewers.
4. 04 Design a search typeahead (autocomplete) service for Facebook that returns suggestions within tens of milliseconds.