The direct report count was easy enough, just build an adjacency list.
Clarify requirements and edge cases, then design a solution that preprocesses the org chart into a graph (e.g., adjacency list) to enable efficient lookups. Implement lookUp by traversing the graph to compute direct and transitive reports, and determine role based on whether the person has direct reports. Discuss time/space trade-offs and potential optimizations like caching or memoization.
Pro tip: Proactively discuss how your solution scales to large org charts and frequent lookups, and mention that you'd validate the input for cycles or missing managers to ensure robustness.
Ask about input format, expected size, frequency of lookups, and edge cases like cycles, multiple managers, or missing persons. Confirm the definition of 'role' and 'transitive reports'.
Decide on an adjacency list (map from manager to list of direct reports) for efficient traversal. Consider if preprocessing (e.g., building the graph once) is acceptable.
For a given name, retrieve direct reports from the map. If none, role is 'IC'; else 'Manager'. Compute transitive reports via DFS/BFS from the person, counting all descendants.
Discuss time complexity: O(1) for direct reports, O(N) for transitive reports in worst case. Suggest memoization or caching for repeated lookups, and consider space-time trade-offs.
Address cycles (use visited set), missing managers (treat as roots), and multiple managers (if allowed, decide on representation). Test with small examples.
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