OOPs, concepts like encapsulation, abstraction, and polymorphism in depth. Database SQL/NoSQL, normalization, etc. The coding question was very straightforward but its evolving constraints were very pushing. Q. Given an array of size n with elements ranging from 1 to k. there is at least one repeating element in the array and you have to return any of those repeating elements. k<n. E.g. ar = {1,1,2,3,4,2,4,5} ans will be 1 or 2 or 4. any of these three will work.