Activity

Create a train system with 3 subway lines.

• Red Line
• Green Line
• Orange Line

Each subway line has multiple stops.

• Red
  • South Station
  • Park Street
  • Kendall
  • Central
  • Harvard
  • Porter
  • Davis
  • Alewife
• Green
  • Government Center
  • Park Street
  • Boylston
  • Arlington
  • Copley
  • Hynes
  • Kenmore
• Orange
  • North Station
  • Haymarket
  • Park Street
  • State
  • Downtown Crossing
  • Chinatown
  • Back Bay
  • Forest Hills

Notice that all 3 subway lines intersect at Park Street, but there are no other intersection points.

Your goal is to write a function named stopsBetweenStations that will accept

• Start Line
• Start Station
• End Line
• End Station

And the function will return how many stops the rider must travel.

Examples:

stopsBetweenStations('Red', 'Alewife', 'Red', 'Alewife') // 0
stopsBetweenStations('Red', 'Alewife', 'Red', 'South Station') // 7
stopsBetweenStations('Red', 'South Station', 'Green', 'Kenmore') // 6

Hint: You should draw the subway system first so you can visualize how many stops each subway line has and how they intersect.