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Meta·Software Engineer·Online Assessment (OA)·Junior

Junior
May 2026

Summary

Straightforward Meta SWE screen, just a basic array sum problem. Nothing tricky, pretty much a warmup question.

Questions Asked (1)

Q1

Given an array of integers, write a function that returns the sum of all its elements.

Algorithms & Data Structures
Author's notes

Pretty much as vanilla as it gets.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem constraints (e.g., array size, integer range, empty array handling) and then propose a simple linear iteration to compute the sum. Discuss potential optimizations like using built-in functions or parallel reduction for large arrays, and mention edge cases such as overflow and empty input.

Pro tip: Demonstrate awareness of production concerns: ask whether the array can be empty, contain negative numbers, or cause integer overflow, and suggest using a 64-bit integer or language-specific safe sum if needed. This shows you think beyond the basic algorithm.

1. Clarify requirements and constraints

Ask about input size, data types, possible empty array, and expected output type. Confirm whether the array can be modified or if additional memory is allowed.

2. Outline a simple approach

Propose iterating through the array once, maintaining a running sum. Mention time complexity O(n) and space complexity O(1).

3. Discuss edge cases and optimizations

Address empty array (return 0), negative numbers, integer overflow, and potential use of built-in functions or parallel reduction for very large arrays.

4. Write clean code

Implement the function with clear variable names, proper initialization, and handling of edge cases. Use language-appropriate syntax.

5. Test with examples

Walk through a few test cases: empty array, single element, positive and negative numbers, and large values to check overflow.

Key Points to Mention

  • Time complexity O(n) and space complexity O(1)
  • Handling empty array by returning 0
  • Potential integer overflow and using appropriate data types (e.g., long)
  • Using built-in functions like sum() in Python or reduce() in JavaScript
  • Parallel reduction for large arrays to improve performance
  • Clarifying whether the array can be modified or if additional memory is allowed

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