Round 1: Machin Code - Flight Inventory Management System
Problem Statement:
Design an application for flight inventory and booking management systems. Where every day multiple flights are flying on different sectors and flights can have multiple fares and for each fare there will be a list of seats.
Assumptions:

• There is a supplier that is providing flight data.
• Flights can have multiple fare Type and for each fare Type airline is providing an available seat list.
• If a seat is already booked, other users can't book the same seat.
• Take today's date as 1.
• For departDate simple number is provided like - 1, 2, 3, 4, etc
• For time, assume its 24 hour format and will be a decimal number.
• User fund will be a decimal number only.

Features:

• AddUser(userld, name, funds)
Return user details
Output:- <u1, name, funds>
• SearchFlight(from, to, departDate, paxCount)
Return available flights for given request in below format. (for the same date and if all available seats are equal or more than provided pax count).
Output:- <flightNumber, airline, from, to, departDate, depart Time, price, fare Type, List< seat >>
• Book flight(userld, from, to, flightNumber, departDate, fareType, list< seat>)
  Book flight if all seats are available with the same fareType and the user has enough funds in his/her wallet. Deduct funds from userAccount for booking and return bookingld.
  If it fails, then return a proper error message.

##Bonus Question

• SearchFlightByPreferedAirline(from, to, departDate, paxCount, preferredAirline, sortBy, SortType)
  Return available flights for given request in below format
  Output:- <flightNumber, airline, from, to, departDate, depart Time, price, List< seat>>

Create entities and service classes such that if new requirements come code will be extensible.

• Commands(Test cases):
  AddUser(userld, name, funds)
  ADDUSER u1 Vinit 5000
  ADDUSER u2 Neha 1500
• SearchFlightfrom, to, departDate, paxCount)
  SEARCHFLIGHT DEL BLR 2 1
  SEARCHFLIGHT DEL BLR 22
  SEARCHFLIGHT DEL HYD 2 22
• Book flight(userld, from, to, flightNumber, airline, departDate, fare Type, list< seat>)
  BOOK u1, DEL, BOM, 111, 6e, 2, F1, 10a, 11c, 20b
  BOOK u1, DEL, BOM, 211, 6e, 2, F2, 10a, 11c, 20b
  BOOK u2, DEL, BOM, 141, 6e, 2, F4, 32e
• SearchFlight(from, to, departDate, paxCount, preferredAirline, sortBy, SortType)
  SEARCHFLIGHT DEL, BLR, 2, 1, AI, PRICE, DESC

Guidelines:

• Do not implement user/admin authentication
• Input can be read from a file or STDIN or coded in a driver method.
• Output can be written to a file or STDOUT.
• Feel free to store all interim/output data in-memory.
• Restrict internet usage to looking up syntax
• You are free to use the language of your choice.
• Save your code/project by your name and email it. Your program will be executed on another machine. So, explicitly specify dependencies, if any, in your email.

Expectation

• Code should be Demo-able and functionally complete.
• Code should fail gracefully with a proper error message for corner/invalid cases, use exceptions for handling these cases.
• Code should be modular, try thinking in terms of Object-Oriented Design.
• Input can be taken from the command line or in the main function.
• Do not use any database or NoSQL store, use in-memory data structure.
• Do not create any Ul for the application
• Driver class can be designed as per your choice, but it should cover all the scenarios. : Optional Implement unit test
  Flight Data:
  

Verdict : Sortlisted (Interviewer was impressed because i have written scalable code)

Round 2: PS DS round

1. https://leetcode.com/problems/linked-list-cycle/description/
2. https://leetcode.com/problems/word-break/description/
3. https://leetcode.com/problems/trapping-rain-water/description/

Verdict : Shortlisted (able to solve all 3 question in 1 hr)

Round 3 : HM Round

1. HM focused on my resume, probing deeply into my experiences, roles and projects.
2. Focused on what i have done challenging task in my project.
3. Asked about unit test written in project. (reason for rejection)
4. Behavorial question.

Final verdict: Rejected.