It was one of their datascience group. Initially when the interviewer asked a question on LRU cache design. I solved it using DS as I assumed the interviwer is expecting the underlying datastructure how a cache would work I explained using a doubly linked list and hashmap and coded it , a running neat code with all the methods properly explained and taking care of all edge cases. Guess what when he asked me where is an interface , I said we can have one and I will rather make it an abstract class and it will have few methods different for eviction policy and few common methods. He didn't even ask me the logic of what I did. Since, he had no ability to understand the ds or even bothered with what I wrote. He was not even there when I was doing the question and not one review question on my data structure that I used. Then he gave me a design question where I wrote two service classes , basic data models, customised exception handing, one server all in one hr , checked it out on git and given him. Basically I felt they are not technical enough to take your interview . If there was a negative button I would have given them