4 Rounds including 1 managerial & 1 Director round. 1st and 2nd Round - Technical - DSA questions, Tree traversal, Medium level DP, famous balanced parentheses problem, 3 - managerial - Basic design round based on an Elevator system 4 - Director - Behavioural Question, previous exp

First round was Hackerrank round which included aptitude and 2 coding questions . They called me for f2f interviews then . 1st round Questions based on resume , difference between soa and microservices ,2 coding questions , one was longest unique substring and other was tree question . Given a small amount of memory , you have to represent 1 to 1 billion numbers in it . Question which would be asked is whether the number is present in the memory or not . 2nd round Design round , design a queuing mechanism , high level as well as low level design . 3rd round 2 puzzles followed by a ds question .I asked the interviewer , if we could use extra space , he said yes , so I stopped thinking about avoiding extra space . Interviewer should have told in this case to avoid extra space . I could have then think other way round . Did not get through the next rounds .