Passed most test cases on this one, which felt fine at the time.
Start by reproducing the error and examining logs to understand the failure. Then systematically trace the request flow through the API layers, isolating the faulty component. Finally, implement a fix, verify it with tests, and consider edge cases to prevent regressions.
Pro tip: Demonstrate a methodical debugging process by verbalizing your hypotheses and how you test them. Also, mention writing a regression test for the bug to show you care about long-term code health.
Run the API and trigger the error to see the exact symptoms. Check logs, error messages, and stack traces to gather clues about the failure point.
Trace the request through the API layers (routing, controllers, services, data access) to narrow down where the error occurs. Use debugging tools or add temporary logging if needed.
Inspect the suspect code and related dependencies to determine why the error happens. Consider common issues like incorrect data handling, misconfigured endpoints, or dependency mismatches.
Make the necessary code changes to resolve the issue. Write or run tests to confirm the fix works and doesn't break other functionality.
Add a regression test that specifically covers the bug scenario. Review similar code paths for potential related issues and document the fix if needed.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Clarify the data structure of a token (e.g., object with an expiration timestamp) and the definition of 'unexpired' (e.g., expiration time > current time). Then iterate through the list, comparing each token's expiration to the current time, and count those that are still valid. Discuss edge cases like empty list, null tokens, and time zone handling.
Pro tip: Mention that you would use a single pass with O(n) time and O(1) space, and that you'd consider using a functional approach like filter and length for readability, but be prepared to discuss performance trade-offs. Also, proactively ask about the time source (e.g., system clock vs. injected clock) to show awareness of testability.
Ask questions to understand the token structure, how expiration is represented, and what 'unexpired' means (e.g., expiration timestamp > now). Confirm input format and expected output.
Decide on a simple iteration approach. If tokens are objects, access the expiration field; if timestamps, compare directly. Consider using a counter variable.
Discuss handling empty list, null tokens, invalid timestamps, and time zone consistency. Mention whether to ignore or throw errors for malformed tokens.
Write clean code with meaningful variable names. Walk through a small example to verify logic, and mention unit tests for boundary conditions.
State time and space complexity (O(n) time, O(1) space). If needed, discuss potential optimizations like early termination if list is sorted by expiration.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.