Power Grid Maintenance

Given an undirected graph of c stations whose connectivity is fixed, process queries that either mark a station offline or ask which operational station with the smallest id resolves a maintenance check for station x (if x is online it answers itself, otherwise return the smallest-id online station in x's connected component or -1 if none). The core challenge is to precompute components and support dynamic deletions while keeping track of the minimum alive id in each component for fast query answers.