Ziphq·Software Engineer·Technical Phone Screen·Intermediate

Intermediate

Jun 2026

Summary

Ziphq software engineer interview with a coding question focused on map traversal and conditional logic. Pretty straightforward problem but the details matter more than they first appear.

Questions Asked (1)

You have a hash map where each key maps to a string value. You're given two helper functions: one that checks if a value is valid, and one that translates it. In a single pass, replace every valid value with its translated version and return the updated map.

Algorithms & Data StructuresTechnical Trade-offs

Author's notes

Seemed simple at first but the 'single pass' constraint is doing a lot of work in that problem statement.

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AI HintsAI Generated

Suggested Approach

Clarify the problem constraints and the behavior of the helper functions, then propose a single-pass iteration over the map's entries, applying the validity check and translation in place. Discuss trade-offs such as mutating the original map versus creating a new one, and consider edge cases like null values or concurrent modification.

Pro tip: Mention that you would avoid modifying the map while iterating over it directly; instead, collect entries to update or use an iterator's setValue method to prevent ConcurrentModificationException. Also, highlight the importance of understanding the helper functions' time complexity and side effects.

1. Clarify requirements and constraints

Ask about the map's mutability, whether the helper functions have side effects, and if the translation should be done in-place or return a new map. Confirm the definition of 'valid' and 'translated'.

2. Choose iteration strategy

Decide between using an iterator with setValue, entrySet with a temporary collection, or streams (if allowed). Consider performance and readability.

3. Implement single-pass logic

Iterate over each entry, check if the value is valid using the helper, and if so, replace it with the translated value. Ensure no concurrent modification issues.

4. Handle edge cases and errors

Address null keys/values, empty map, and potential exceptions from helper functions. Discuss whether to skip invalid values or throw errors.

5. Analyze complexity and trade-offs

State time complexity O(n) and space complexity O(1) if in-place, or O(n) if new map. Discuss pros and cons of mutating vs. immutable approach.

Key Points to Mention

Use of iterator's setValue method to safely modify map during iteration
Time complexity O(n) where n is number of entries, assuming helper functions are O(1)
Space complexity considerations: in-place modification vs. creating a new map
Handling of null values and potential exceptions from helper functions
Avoiding ConcurrentModificationException by not using map.put during iteration
Clarifying whether the helper functions are pure or have side effects

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