Bus Route Earliest Arrival

Given bus routes / schedules, travel times between stops, waiting times, origin, destination, and departure time, compute the earliest arrival time. Requirements Given several bus route timetables, compute the earliest arrival time. Input concept: Routes with ordered stops. Travel time between adjacent stops. Waiting / departure times. Query: (start_location, end_location, departure_time). Output: earliest arrival time. You should discuss test cases and time complexity. Notes Model this as a time-dependent graph. A state is (stop, current_time). From a stop, eligible outgoing edges are bus departures at or after current_time; edge cost is waiting time plus travel time. If all edge costs are non-negative, Dijkstra-style traversal works. For simple inputs, a route scan may be enough. For repeated queries, pre-index departures by stop and use binary search to find the next eligible bus. Preparation Practice turning transit schedules into graph edges with departure and arrival times. Implement a single-query version using a priority queue. Prepare follow-ups for transfer limits, overnight schedules, repeated queries, and real-time delays.