Stripe·Software Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say

May 2026

Summary

Stripe coding screen for a software engineer role, basically one problem the whole time: text wrapping. Sounds trivial until you're actually coding it under pressure and the interviewer starts asking about edge cases you didn't think about.

Questions Asked (1)

Given a long string and a maximum line width L, implement a function that breaks the text into lines. You need to handle two variants: one that cuts hard at exactly L characters regardless of word boundaries, and one that breaks at the last whitespace before the limit. Also handle edge cases like single words longer than L and trailing whitespace.

Algorithms & Data StructuresTechnical Trade-offs

Author's notes

I went straight for the word-aware version because it felt more 'real' and I thought it would impress them.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements and edge cases, then propose a clean interface that handles both hard and soft wrapping variants. Implement each variant with careful index management, and discuss trade-offs like time/space complexity and handling of long words and trailing whitespace.

Pro tip: Demonstrate production awareness by discussing how you'd handle Unicode characters (e.g., combining marks, emojis) and whether the width limit is in bytes or code points, as this is a common pitfall in real-world text processing.

1. Clarify Requirements and Edge Cases

Ask about the expected behavior for edge cases: single words longer than L, trailing whitespace, multiple consecutive spaces, and whether the input can contain newlines. Confirm if the output should preserve or trim whitespace.

2. Design the Interface

Propose a function signature that takes the string and L, and returns a list of lines. Consider a parameter to switch between hard and soft wrapping, or implement two separate functions.

3. Implement Hard Wrapping

For hard wrapping, simply slice the string into chunks of length L. Handle the last chunk if the string length is not a multiple of L. Discuss whether to include trailing whitespace in the last line.

4. Implement Soft Wrapping

For soft wrapping, iterate through the string, find the last whitespace before L, break there, and continue. If no whitespace is found, break at L (or handle long words by breaking them). Trim trailing whitespace from each line.

5. Analyze Complexity and Trade-offs

Discuss time and space complexity: both approaches are O(n) time and O(n) space for the output. Mention trade-offs: hard wrapping is simpler but may split words; soft wrapping is more readable but requires more logic and may still split long words.

Key Points to Mention

Handling of words longer than L: either break them at L or allow them to exceed L, depending on requirements.
Trailing whitespace: trim it from each line to avoid extra spaces, but consider if it should be preserved in some cases.
Unicode and character encoding: width may be measured in code points, not bytes, and grapheme clusters should not be split.
Efficiency: avoid repeated string concatenation; use a list to collect lines and join at the end.
Edge cases: empty string, L <= 0, string with only whitespace, and multiple consecutive spaces.
Testing: include unit tests for boundary conditions like exact multiples of L and whitespace at the break point.

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