araluce/trip_sorter

Trip sorter

Maximum amount of time allowed: 2 hours

Task

You are given a stack of boarding cards for various transportations that will take you from a point A to point B via several stops on the way. All of the boarding cards are out of order and you don't know where your journey starts, nor where it ends. Each boarding card contains information about seat assignment, and means of transportation (such as flight number, bus number etc). Provide an API that let's you sort this kind of list and present back a description of how to complete your journey. For instance the API should be able to take an unordered set of boarding cards, provided in a format defined by you, and produce this list:

• Take train 78A from Madrid to Barcelona. Sit in seat 45B.
• Take the airport bus from Barcelona to Gerona Airport. No seat assignment.
• From Gerona Airport, take flight SK455 to Stockholm. Gate 45B, seat 3A. Baggage drop at ticket counter 344.
• From Stockholm, take flight SK22 to New York JFK. Gate 22, seat 7B. Baggage will we automatically transferred from your last leg.
• You have arrived at your final destination.

The list should be defined in a format that's compatible with the input format. The API is to be an internal Ruby API so it will only communicate with other parts of a Ruby application, not server to server, nor server to client. Document the input and output your API accepts / returns. Requirements

• Use object oriented Ruby for the implementation.
• Do not use any 3rd party framework. Start all code from scratch.
• The structure of the code should be extendable to make building in support for any means of transportation / extra information required about a specific type of transportation easy.
• The implementation of your sorting algorithm should work with any set of boarding passes, as long as there is always an unbroken chain between all the legs of the trip. Ie. it's one continuous trip with no interruptions.
• The algorithm doesn't need to consider that departure / arrival are in the correct order. In fact there is no information about any such times on the boarding passes. It is just assumed that your next connection is waiting for you when you arrive at a destination.
• The algorithm should have the lowest possible order of complexity (Big O notation) you could think of.