The stack part clicked fast but I fumbled a bit on how to serialize the path for the hash map key.
Use a stack to track the active call path, pushing on call events and popping on return events, and record the current path at each event. Then, use a hash map to count the frequency of each distinct path. Clarify the log format and whether paths are represented as sequences of function names or unique call IDs.
Pro tip: Clarify whether the log includes timestamps and if multiple events can occur at the same time; also discuss handling of malformed logs or unmatched returns to demonstrate robustness.
Ask about the structure of log entries (e.g., call/return, function names, IDs) and whether paths are defined by function names or unique call instances. Confirm the output format and any constraints.
Use a stack to maintain the current call path. On a call event, push the function identifier; on a return event, pop the top. Record the current path after each event.
Use a hash map to count how many times each distinct path appears. Convert the stack to a string or tuple to use as a key.
Consider unmatched returns, nested calls, and empty paths. Discuss error handling or assumptions (e.g., log is well-formed).
Time complexity is O(n) for n events, but path recording may add overhead. Discuss trade-offs and potential optimizations like incremental hashing.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.