Netflix·Software Engineer·Technical Phone Screen·Intermediate

Intermediate

May 2026

Summary

Netflix coding screen for a software engineer role, basically one problem with three increasingly annoying rule levels bolted on. The kind of question that feels simple until you're twenty minutes in and realizing you missed an edge case from level one that now breaks level three.

Questions Asked (1)

Implement a string-to-integer parser from scratch, without using any built-in conversion methods, across three rule levels: first handling optional leading minus signs and throwing on overflow or non-digit characters; then tightening validation for any special character; then adding strict leading-zero rules where only a single zero prefix is allowed.

Algorithms & Data StructuresTechnical Trade-offs

Author's notes

The first level felt manageable.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the three rule levels and their expected behaviors, then implement a single parser that can be toggled between levels via a parameter or separate functions. Walk through edge cases for each level, explaining how validation and overflow handling change. Emphasize clean code, early returns, and comprehensive testing.

Pro tip: Mention that you would write unit tests for each rule level, including boundary cases like INT_MIN, INT_MAX, and strings with leading zeros, to demonstrate production-ready thinking.

1. Clarify requirements and edge cases

Ask questions to confirm the exact rules for each level, such as whether whitespace is allowed, how to handle empty strings, and the expected behavior for overflow (throw exception vs. return sentinel).

2. Design the parser structure

Decide on a modular approach: either a single function with a level parameter or separate functions for each rule set. Plan how to handle sign, digits, and validation logic.

3. Implement level 1: basic parsing with overflow and non-digit checks

Iterate through characters, handle optional leading minus, accumulate digits, and throw on overflow or non-digit characters. Use integer arithmetic to detect overflow before it happens.

4. Extend to level 2: stricter validation

Add checks for any special characters (e.g., plus sign, whitespace) and ensure only digits and an optional leading minus are allowed. Throw on any other character.

5. Extend to level 3: leading-zero rules

Enforce that only a single zero prefix is allowed (e.g., '0' is valid, '00' or '01' are invalid). Adjust validation to reject strings with multiple leading zeros.

Key Points to Mention

Overflow detection: use checks like result > (INT_MAX - digit) / 10 before multiplying and adding.
Handling negative numbers: track sign separately and apply at the end, being careful with INT_MIN.
Character validation: ensure each character is between '0' and '9', and handle non-ASCII or Unicode digits if relevant.
Leading zero rules: clarify that '0' alone is allowed, but '00' or '01' are not; implement by checking if first digit is '0' and length > 1.
Error handling: throw exceptions with clear messages for invalid input or overflow, as specified.
Testing: include unit tests for each level covering valid inputs, invalid inputs, boundary values, and edge cases like empty string and lone minus sign.

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