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Extend an existing system with additional constraintsHandle compatibility rulesImplement conditional object matchingMaintain correctness under more rulesStill pass tests without redesigning everything
⏰ Time limit: 75 minutes❌ Do NOT change class names❌ Do NOT change method signatures❌ Do NOT modify test file❌ No print statements✅ Use only given structure✅ Return values exactly as required
CARBIKEvehicle_idvehicle_type
CAR_ONLYBIKE_ONLYANYCAR_ONLY → only CARBIKE_ONLY → only BIKEANY → both
One vehicle → one spotVehicle cannot be parked twiceSpot can hold only one vehicleVehicle must be compatible with spot typeParkingLot assigns first available compatible spot
Store:vehicle_idvehicle_type
Spot is FREENo vehicle assignedSpot is FREEVehicle type is compatible with spot typeIf can_park(vehicle) is False → return FalseElse:Assign vehicleMark spot as OCCUPIEDReturn TrueIf spot is FREE → return FalseElse:Remove vehicleMark spot as FREEReturn TrueReturn True if FREE, else FalseReturn vehicle if OCCUPIEDElse return None
spots is a list of ParkingSpot objectsParkingLot does NOT create spotsIt only manages themIf vehicle already parked anywhere → return FalseFind first FREE & compatible spotPark vehicle thereReturn TrueIf no such spot → return FalseFind spot with this vehicleIf found:UnparkReturn TrueElse → return FalseReturn count of FREE spots
ParkingLot coordinatesParkingSpot enforces compatibilityVehicle is just dataNo spot scanning shortcutsValidation happens before mutation
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Day 7.5 — Parking Lot (Constraint-Heavy Variant)
Perfect.
Below is Day 7.5 — Extended Machine Coding (Level-1+) in the same strict, interview-ready format.
This day is intentionally harder than Day 7, but still safe for SDE-1.
No new concepts — just more constraints + deeper thinking.
🟢 Day 7.5 — Parking Lot (Constraint-Heavy Variant)
This is the bridge between “I can code” and “I can handle real machine-coding interviews.”
🎯 Day 7.5 Objective
By the end of Day 7.5, the candidate should be able to:
This day tests discipline, not intelligence.
⏱ Interview Simulation Rules
Give these to the candidate before starting:
🧠 What’s New Compared to Day 7?
Day 7
Day 7.5
Single vehicle type
Multiple vehicle types
Any spot works
Spot–vehicle compatibility
Simple rules
More validation
Same structure
Same structure + more logic
There are no rows in this table
⚠️ No new abstractions allowed
🚗 Problem — Parking Lot with Vehicle & Spot Types
📋 System Rules (Read Carefully)
Vehicle Types
Each vehicle has:
Parking Spot Types
Each spot can park:
Parking Rules
🧱 Class Definitions (DO NOT MODIFY)
class Vehicle:
def __init__(self, vehicle_id: str, vehicle_type: str):
pass
class ParkingSpot:
def __init__(self, spot_id: int, spot_type: str):
pass
def can_park(self, vehicle: Vehicle) -> bool:
pass
def park(self, vehicle: Vehicle) -> bool:
pass
def unpark(self) -> bool:
pass
def is_free(self) -> bool:
pass
def get_vehicle(self):
pass
class ParkingLot:
def __init__(self, spots: list):
pass
def park_vehicle(self, vehicle: Vehicle) -> bool:
pass
def unpark_vehicle(self, vehicle_id: str) -> bool:
pass
def get_available_spots(self) -> int:
pass
📌 Detailed Requirements (NO GUESSING)
Vehicle
__init__
ParkingSpot
Initial State
can_park(vehicle)
Return True if:
Else return False.
park(vehicle)
unpark()
is_free()
get_vehicle()
ParkingLot
__init__(spots)
park_vehicle(vehicle)
unpark_vehicle(vehicle_id)
get_available_spots()
🧠 Expected Thinking Process
Candidate should realize:
🧪 (Given to Candidate)
class Vehicle:
def __init__(self, vehicle_id: str, vehicle_type: str):
pass
class ParkingSpot:
def __init__(self, spot_id: int, spot_type: str):
pass
def can_park(self, vehicle: Vehicle) -> bool:
pass
def park(self, vehicle: Vehicle) -> bool:
pass
def unpark(self) -> bool:
pass
def is_free(self) -> bool:
pass
def get_vehicle(self):
pass
class ParkingLot:
def __init__(self, spots: list):
pass
def park_vehicle(self, vehicle: Vehicle) -> bool:
pass
def unpark_vehicle(self, vehicle_id: str) -> bool:
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