FabHotels interview questions

It was F2F interview. The office was nice, HR was nice. First interview was with EM he asked question from resume regarding cache, optimzation techniques i used and microservices design patterns i have used in previous orgs. 1st round : System design of captcha for authentication. Highly Scalable. System design of a notification service which sends notification for payment invoice and bookings. should be highly scalable and open to integrations for new vendors. 2nd round : Started with distributed systems . 1) what is CAP theorem. 2) In what system CP is required over Availablity. 3) What is split brain problem 4) System design of Medium, for high scalibility and fault tolerant.