Coding Interview Question on Metro Smart Card System

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Problem Statement :
Our Company has been asked to implement Metro Smart Card System (MSCS) for Delhi City. For this application assume there is a single metro line covering 10 stations linearly.

The stations name are A1,A2,A3,A4,A5,A6,A7,...A10. The travel can be in any direction from any station except A1 and A10.

Travelers have smart card that behave just like any other regular debit card that has an initial balance when purchased. Travelers swipe in when they enter a metro station and swipe out when they exit. Card balance is automatically updated at swipe out.

Objective :

Objective of this exercise is to create an automated system that has following functionality.

Card should have a minimum balance of Rs. 50 at swipe-in. At swipe-out, system should calculate the fare based on below strategies. The fare must be deducted from the card. Card should have the sufficient balance otherwise user should not be able to exit.

Weekday - Rs 7 * (Number of stations travelled)
Weekend - Rs 5.5 * (Number of station traveled if it is Saturday or Sunday )
(* there could be more such fare strategies in future).

Additionally system needs to have functionality to generate some statistics/report defined below. So system needs to provide following API.

• API to get total foot-fall(swipe-in + swipe-out) for a given station.
• API to generate a "per-card report" on demand. It should print the following information on console.

      Card<number> used to travel from <source_station> to station <destination_station>. Fare is Rs<x> and balance on card is Rs<x>.

CLICK Code Sample   to download the sample code for this problem.
Above code sample is created by using command line design pattern which is appropriate for this problem. However this is just for reference and you could practice this problem to find more appropriate solution.