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rippling·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Jul 2026

Summary

Rippling SWE interview with a poker hand comparison problem. The design angle was more interesting than I expected, less about grinding through cases and more about how you structure the solution.

Questions Asked (1)

Q1

Given a fixed set of poker hand-ranking rules, write a function that compares two players' hands and returns the winner. Input is two string arrays representing each player's cards.

Algorithms & Data StructuresTechnical Trade-offsSystem Design
Author's notes

The problem itself isn't that hard but the design question buried inside it is.

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AI HintsAI Generated

Suggested Approach

First, clarify the input format and hand-ranking rules, then outline a plan to evaluate each hand by categorizing it into a rank and comparing ranks, using tiebreakers when necessary. Implement a function that parses each hand, determines its rank and key cards, and compares them to return the winner.

Pro tip: Mention that you would write unit tests for edge cases like ace-low straights and flush vs. straight, and discuss how you'd handle ties or invalid inputs gracefully.

1. Clarify Requirements

Ask about input format (e.g., '2H' for two of hearts), hand size (5 cards), and whether ace can be low. Confirm the exact ranking order and tiebreaker rules.

2. Design Hand Evaluation

Plan a function to evaluate a hand: count ranks and suits, check for straights/flushes, and assign a numerical rank (e.g., 1 for high card, 9 for straight flush).

3. Implement Comparison

Compare two hands by their rank; if equal, compare tiebreaker values (e.g., highest card in the combination). Return the winner or a tie.

4. Handle Edge Cases

Consider ace-low straights (A-2-3-4-5), multiple players, and invalid inputs. Discuss how to handle ties and ensure code robustness.

5. Test and Optimize

Write unit tests for all hand types and edge cases. Discuss time/space complexity (O(1) for fixed hand size) and potential optimizations.

Key Points to Mention

  • Hand ranking order: high card, pair, two pair, three of a kind, straight, flush, full house, four of a kind, straight flush.
  • Tiebreaker rules: compare highest card in the combination, then next highest, etc.
  • Special case: ace can be high or low in a straight (A-2-3-4-5 is a 5-high straight).
  • Data structures: use hash maps to count ranks and suits efficiently.
  • Modular design: separate hand evaluation from comparison for clarity and testability.
  • Testing: cover all hand types, ties, and invalid inputs.

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