You're designing the elevator system for a 20-story office tower. Each elevator needs to track its current floor, direction, and the list of floors it must visit. It should handle requests from inside (passengers pressing floor buttons) and outside (hall call buttons).

Code

enum Direction { UP, DOWN, IDLE }

class Elevator {
  private id: number
  private currentFloor: number = 0
  private direction: Direction = Direction.IDLE
  private destinationFloors: SortedSet<number>
  private capacity: number = 10
  private currentLoad: number = 0

  addDestination(floor: number): void { /* ... */ }
  move(): void { /* ... */ }
  isAvailable(): boolean { /* ... */ }
  distanceTo(floor: number): number { /* ... */ }
}

Question

What's the best way to model an individual Elevator?

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Design Elevator System

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Elevator Class Design

Data Structure Selection

Code

enum Direction { UP, DOWN, IDLE }

class Elevator {
  private id: number
  private currentFloor: number = 0
  private direction: Direction = Direction.IDLE
  private destinationFloors: SortedSet<number>
  private capacity: number = 10
  private currentLoad: number = 0

  addDestination(floor: number): void { /* ... */ }
  move(): void { /* ... */ }
  isAvailable(): boolean { /* ... */ }
  distanceTo(floor: number): number { /* ... */ }
}

Question

What's the best way to model an individual Elevator?