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Edge Case Handling and Debugging Questions

Covers the systematic identification, analysis, and mitigation of edge cases and failures across code and user flows. Topics include methodically enumerating boundary conditions and unusual inputs such as empty inputs, single elements, large inputs, duplicates, negative numbers, integer overflow, circular structures, and null values; writing defensive code with input validation, null checks, and guard clauses; designing and handling error states including network timeouts, permission denials, and form validation failures; creating clear actionable error messages and informative empty states for users; methodical debugging techniques to trace logic errors, reproduce failing cases, and fix root causes; and testing strategies to validate robustness before submission. Also includes communicating edge case reasoning to interviewers and demonstrating a structured troubleshooting process.

HardSystem Design
0 practiced
Design a strategy to guarantee backward and forward compatibility for a protobuf contract used by multiple teams. Address edge cases: optional->required transitions, unknown fields, enum value removals, default values, version negotiation, and testing approaches to catch contract breaks before deploy.
HardSystem Design
0 practiced
Design a testing and rollout strategy that prevents feature-flag framework bugs from leaking incomplete experiments to customers. Include unit and integration tests, canary rollout patterns, fallback behavior, concurrency tests for flag evaluation races, and monitoring to detect flag inconsistencies in production.
HardTechnical
0 practiced
You detect data corruption that only appears for inputs larger than 2GB. Explain a methodical debugging and prevention plan: check 32-bit counters, file APIs, streaming vs in-memory processing, third-party libs, OS limits, and test harnesses to reproduce the issue and verify fixes.
EasyTechnical
0 practiced
Write a concise Python function safe_divide(a, b) that performs input validation and returns a tuple (result, error_message). It should handle invalid types, division by zero, and extreme values. Keep implementation clear and defensive, include a short docstring, and ensure error_message is actionable (suitable for logs).
HardSystem Design
0 practiced
Architect a multi-region, zero-downtime plan to add a non-nullable column without default to a user table containing 1B rows. Include steps for schema change, backfill, validation, how to maintain service compatibility, replication lag handling, and rollback plans for partial backfill states.

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