Meta·Software Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say

May 2026

Summary

Meta SWE coding question involving filtering and aggregating employee counts across office locations. Pretty straightforward list manipulation problem but the tuple structure tripped me up a bit.

Questions Asked (1)

Given a list of office locations where each entry contains a list of employee counts and a boolean indicating whether the location is open, return the summed employee count for each open location in the original order.

Algorithms & Data Structures

Author's notes

The problem itself is not hard but I fumbled the input structure at first.

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AI HintsAI Generated

Suggested Approach

Clarify the input structure and edge cases, then propose a single-pass solution that iterates through the list, checks the boolean flag, and sums the employee counts for open locations. Discuss time and space complexity, and consider if any optimizations or alternative approaches are worth mentioning.

Pro tip: Always confirm the data types and whether the employee counts list can be empty or contain non-integers; this shows attention to detail and prevents incorrect assumptions. Also, mention that you would write unit tests for edge cases like all locations closed or empty input.

1. Understand the problem

Restate the problem in your own words and ask clarifying questions about the input format, expected output, and edge cases.

2. Outline the approach

Explain that you will iterate through each location, check if it's open, and if so, sum its employee counts. Emphasize maintaining original order.

3. Analyze complexity

State that the time complexity is O(n*m) where n is number of locations and m is average number of employee counts per location, and space complexity is O(1) extra if summing on the fly.

4. Handle edge cases

Discuss edge cases such as empty input, all locations closed, or locations with empty employee count lists, and how your solution handles them.

5. Test with examples

Walk through a simple example to verify the solution, and possibly mention writing unit tests.

Key Points to Mention

Clarify input structure: list of locations, each with a list of employee counts and a boolean.
Single-pass iteration to check open status and sum counts.
Maintain original order by processing sequentially.
Time complexity: O(total number of employee counts).
Space complexity: O(1) extra space if summing on the fly.
Edge cases: empty input, all closed, empty employee lists.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.