LLD Problem · Hard
Elevator System
Design an elevator control system that schedules multiple cars across many floors efficiently. Key requirements: - Multiple cars with capacity and direction - hall calls (up/down) and car calls (floor) - SCAN/LOOK scheduling - idle car parking strategy - door state machine - emergency + maintenance mode.
Problem statement
Design an elevator control system that schedules multiple cars across many floors efficiently. Key requirements: - Multiple cars with capacity and direction - hall calls (up/down) and car calls (floor) - SCAN/LOOK scheduling - idle car parking strategy - door state machine - emergency + maintenance mode.
Functional requirements
- 01.Request elevator from any floor
- 02.Select target floor inside cabin
- 03.Dispatch the optimal elevator
- 04.Handle direction changes
- 05.Open/close doors safely
Non-functional requirements
- •Real-time response under 1s
- •Fair scheduling under load
Constraints & assumptions
- ›N elevators, M floors
- ›Max capacity per cabin