How would you debug production issues related to DFS Cycle Detection (Directed Graph)?

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Quick interview answer

Debug DFS Cycle Detection (Directed Graph) by confirming blast radius, checking lag/error metrics, grabbing profiles/traces, then mitigating before deep root-cause. Mitigate first, then root-cause. Check symptoms against: Using two-color visited only (misses cross edges in undirected); forgetting disconnected components..

Detailed answer

Production debug playbook for DFS Cycle Detection (Directed Graph): 1) Stabilize: rate-limit, shed load, or roll back if users are hurting. 2) Orient: dashboards for latency, errors, saturation tied to DFS Cycle Detection (Directed Graph). 3) Evidence: traces, profiles, logs with correlation IDs. 4) Hypothesize + prove with a safe experiment. 5) Fix + add a regression test/alert so it cannot silently return. Watch for: Using two-color visited only (misses cross edges in undirected); forgetting disconnected components. Parent context: Mitigate first, then root-cause. Check symptoms against: Using two-color visited only (misses cross edges in undirected); forgetting disconnected components..

Full explanation

Interviewers score structured incident thinking: mitigate → measure → root cause → prevent. Three-color DFS: white=unvisited, gray=in current stack, black=done. Back edge to gray node ⇒ cycle. Works for dependency graphs and course prerequisites.

Follow-up questions

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Parent context — DFS Cycle Detection (Directed Graph)

Mitigate first, then root-cause. Check symptoms against: Using two-color visited only (misses cross edges in undirected); forgetting disconnected components..

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