Samsara·Software Engineer·Technical Phone Screen·Senior

Senior

May 2026

Summary

Samsara software engineer interview with a coding question that was heavier on design thinking than I expected. The problem looked like a parsing exercise but turned into a full conversation about tokenization strategy, edge cases, and complexity tradeoffs.

Questions Asked (1)

Implement a function that converts a plain-text string to HTML, supporting paragraphs (split on two or more consecutive newlines), soft line breaks (single newline becomes <br/>), blockquotes (lines starting with '> '), strikethrough (text), and the constraint that formatting cannot cross paragraph boundaries.

Algorithms & Data StructuresTechnical Trade-offsSystem Design

Author's notes

This one took me longer to scope than to actually code.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements and edge cases, then propose a two-phase approach: first split the input into paragraphs using two or more newlines as delimiters, then process each paragraph independently to handle soft line breaks, blockquotes, and strikethrough. Emphasize that formatting cannot cross paragraph boundaries, so each paragraph is a self-contained unit, which simplifies the implementation and avoids complex state management.

Pro tip: Mention that you would use a regex or a simple state machine to detect strikethrough and blockquotes, but be careful to escape HTML special characters first to prevent injection. Also, discuss how you would handle nested or overlapping formatting, even if not required, to show foresight.

1. Clarify requirements and edge cases

Ask about expected input size, whether HTML escaping is needed, how to handle empty paragraphs, and if blockquotes can contain other formatting. Confirm that formatting cannot cross paragraph boundaries.

2. Design the parsing strategy

Propose splitting the input into paragraphs using a regex like /\n{2,}/. Then process each paragraph independently, applying transformations in a defined order: escape HTML, handle blockquotes, convert soft line breaks, and apply strikethrough.

3. Implement paragraph-level processing

For each paragraph, check if it starts with '> ' to wrap it in <blockquote>. Replace single newlines with <br/>. Use a regex to replace ~~text~~ with <del>text</del>, ensuring it doesn't cross paragraph boundaries.

4. Assemble and test

Wrap each processed paragraph in <p> tags (or <blockquote> if applicable) and join them. Test with edge cases: multiple blank lines, leading/trailing whitespace, strikethrough spanning lines, and blockquotes with soft breaks.

5. Discuss trade-offs and optimizations

Talk about time/space complexity (O(n) time, O(n) space), potential use of a streaming parser for large inputs, and how to handle malformed input gracefully.

Key Points to Mention

Splitting on two or more newlines using regex to define paragraph boundaries.
Escaping HTML special characters (e.g., &, <, >) before applying formatting to prevent XSS.
Processing each paragraph independently to enforce the constraint that formatting cannot cross boundaries.
Order of operations: escape HTML, then blockquotes, then soft line breaks, then strikethrough.
Using regex with non-greedy matching for strikethrough, and ensuring it doesn't match across paragraphs.
Handling edge cases like empty paragraphs, whitespace-only paragraphs, and blockquotes with multiple lines.

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