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Microsoft·Software Engineer·Onsite - Coding / Algorithms·Intermediate

Intermediate
May 2026

Summary

Third round at Microsoft for a software engineering role. It was a LeetCode-style coding problem, a variant of a well-known medium/hard problem, with the input format changed to use two string arrays instead of the original. Had to run tests before wrapping up.

Questions Asked (1)

Q1

Solve a variant of a well-known LeetCode problem (700s difficulty range) where the input is modified to accept two string arrays instead of the original input type.

Algorithms & Data Structures
Author's notes

The core logic wasn't totally foreign but the input change threw me off more than I expected.

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AI HintsAI Generated

Suggested Approach

First, clarify the problem by identifying the original LeetCode problem and how the input modification changes the solution. Then, adapt your algorithm to handle two string arrays, focusing on efficient comparison and data structure choices. Finally, walk through your solution with examples and analyze time/space complexity.

Pro tip: Demonstrate adaptability by discussing how you would handle edge cases like empty arrays or duplicate strings, and mention potential optimizations like using a hash set for O(1) lookups.

1. Clarify the Problem

Ask clarifying questions to confirm the original problem and the exact nature of the input modification. Ensure you understand the expected output and constraints.

2. Identify the Core Algorithm

Recall the original LeetCode problem (likely in the 700s range, such as 771 Jewels and Stones or 709 To Lower Case) and determine how the algorithm needs to change with two string arrays.

3. Design the Solution

Choose appropriate data structures (e.g., hash sets, frequency maps) to efficiently process the string arrays. Outline the steps of your algorithm clearly.

4. Analyze Complexity

Calculate the time and space complexity of your solution. Discuss trade-offs between different approaches.

5. Test with Examples

Walk through your solution with a few test cases, including edge cases like empty arrays or duplicate strings, to verify correctness.

Key Points to Mention

  • Identify the original LeetCode problem and its typical solution.
  • Explain how the input modification affects the algorithm.
  • Use efficient data structures like hash sets for O(1) lookups.
  • Discuss time and space complexity (e.g., O(n+m) time, O(n) space).
  • Handle edge cases such as empty arrays, duplicates, and case sensitivity.
  • Mention potential optimizations or alternative approaches.

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