I own a parking garage that provides valet parking service.
There are three types of parking spots:
- small
- medium
- large
Cars also come in three sizes:
- small
- medium
- large
Rules:
- A small car can fit in any spot
- A medium car can fit in medium or large spots
- A large car can fit only in large spots
You receive a stream of parking events.
Each event is either:
"arrival"with a car size"departure"with the same car size (the car leaves and frees its spot)
Your system must assign a valid spot on arrival and free the spot on departure.
Example input (conceptual):
(arrival, small)
(arrival, large)
(arrival, medium)
(departure, small)
(arrival, large)
...
You need to design a system (API + data structure) that correctly handles spot assignment and freeing while following the size rules.
Maintain three counters (available small/medium/large spots).
On arrival, pick the smallest valid spot for that car type.
On departure, restore availability for the spot type previously assigned to that car.
Track active assignments in a map: car_id → spot_type.
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