Coupang·Software Engineer·Technical Phone Screen·Intermediate

Intermediate

Jun 2026

Summary

Coupang coding round for a software engineer role, basically one parsing and sorting question that sounds easy until you actually sit down to think through the edge cases.

Questions Asked (1)

You're given a list of strings in the format 'product,price,attention'. Parse them into records, skip any malformed entries, and return the product names sorted by price ascending, then attention descending, then product name alphabetically as a tiebreaker. Price and attention are integers. Walk through your approach, data structures, complexity, and write working code.

Algorithms & Data StructuresTechnical Trade-offs

Author's notes

I went straight to splitting on commas and wrapping the int conversions in a try/except to handle malformed rows, which felt right.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and edge cases, then outline a parsing strategy with validation, followed by sorting with a custom comparator. Discuss data structures (e.g., list of tuples) and complexity (O(n log n) time, O(n) space), and finally write clean, working code with tests.

Pro tip: Mention that you would use a stable sort or a single comparator to handle multiple keys, and explicitly discuss how to handle malformed entries (e.g., missing fields, non-integer values) to show attention to detail.

1. Clarify requirements and edge cases

Ask about input size, malformed entry definitions, and tie-breaking rules. Confirm expected output format and any constraints.

2. Design parsing and validation

Split each string by commas, check for exactly three parts, and validate that price and attention are integers. Skip invalid entries.

3. Choose data structures and sorting strategy

Store valid records as tuples (product, price, attention). Sort using a custom key: price ascending, attention descending, product name ascending.

4. Analyze complexity and trade-offs

Time complexity is O(n log n) due to sorting; space is O(n) for storing records. Discuss alternative approaches if needed.

5. Write and test code

Implement the solution in a clean function, handle edge cases, and walk through a small example to verify correctness.

Key Points to Mention

Parsing and validation: splitting by comma, checking field count, and converting to integers with error handling.
Sorting with multiple keys: using a tuple key with negative attention for descending order, or a custom comparator.
Complexity analysis: O(n log n) time for sorting, O(n) space for storing records.
Edge cases: empty input, malformed strings, duplicate products, and large input sizes.
Code clarity: modular functions, meaningful variable names, and comments.
Testing: unit tests for valid and invalid inputs, and verifying sort order.

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