Taxi Booking System: Implement an online taxi booking system for a customer where the customer can select a category to book based on his pickup location and drop location. 
 
Constraints: 
1.      Various categories of taxi will be available like mini, sedan, suv, share, outstation 
2.      Each vehicle is tied to an agency to which it belongs. 
3.      Assume a method exists getDistanceTime (Point a, Point b) which return distance and time taken to travel from a Point A to point B, where Point refers to a model representing the location in terms of latitude and longitude. 
4.      Fare is a factor of city specific fare, distance, time and number of active users in the system. Fare increases as demand increases with a factor of 0.1 * total users requested rides/total inventories when the demand crosses the supply else the fare remains same.  
5.      Active users refer to the users who are trying to book a cab at that time. Dormant users are those who have not created any booking in last 1 week. 
6.      Commission is based on the category selected. Some categories have high commission like suv, luxury, outstation while others can have lower commission 
 
APIs to Implement: 
1.      Find the estimated fare for a booking from point a to point b based on category selected 
2.      Find number of vehicles available and occupied based on category provided at any given point in time 
3.      Total number of bookings based on category given in the date time range supplied 
4.      No of active and dormant users within a date time range. Active users refer to the users who are trying to book a cab at that time. Dormant users are those who have not created any booking in last 1 week. 
5.      Agency wise total revenue generated for a given date range  
6.      Total booking of an agency based on category supplied. 
 
Guidelines: 
o Define a detailed object model for entities required by system 
o Make proper use of Inheritance, Abstraction and interfaces 
o Expect to do proper exception handling of code 
o Have proper commenting in code and should follow best coding practises 
o Use design patterns like Builder, Factory, Visitor etc wherever applicable 
o Justify his/her coding choices i.e. why did he/she choose to define a separate function for a 
feature or why did he/she not define constructor for initialising class 
o Define Enums, Singleton classes where applicable 
o Separation of concern is addressed 
o Implement unit test cases for key sections of his/her code 
o Use Java 8/7 features like functional interfaces, Auto Closeable resources etc. 

Minimum Moves Knight(LC medium): Discussed approach and coded in short time. Discussed test cases edge cases and complexities.

Later asked a follow up about printing the path.Discussed the approach which was correct but code didn't work properly. Even though the interviewer seemed satisfied was ghosted by recruiter that day..Next day called from another number (LOL) and got feedback that feedback is negative. No point asking detail feedback to these.