Microsoft·Software Engineer·Technical Phone Screen
May 2026
Microsoft SWE interview that went deep on string processing fundamentals. One question, but it had a lot of layers: tokenization design, implementation, streaming, testing, and complexity analysis all rolled in.
- Given a text document, count the number of words. Before coding, define your tokenization rules precisely (contractions, hyphenated words, decimals, punctuation, Unicode quotes, whitespace), then implement a function that handles large files or streams, write unit tests for edge cases, and analyze the time/space complexity. Also compare regex-based tokenization against a manual character scanner.
“This looked like a warm-up question until it wasn't.” The rest of the author's notes on Software Engineer interview at Microsoft, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.
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