In the first round, the interviewer asked some technical questions about the environment in which the coding is done. Then a warm up coding question was asked. The questions are pretty much covered in Glassdoor. In the second round, I was asked to design a stack API. I asked a lot of questions regarding how the stack should behave, but I guess I failed to ask the key point... I designed a stack API using a linked list. That way the information would be hidden inside a struct. But I guess that wasn't enough... The interviewer hinted me "what if the user only push one byte of data every time? Don't you think it will be a waste of space?" I then came up with another linked list with only one "next pointer" in it (no pointer to the data), which saves space, I still failed. The reason I used a struct is that I wanted to hide the data from direct manipulation, but I guess what they really wanted was a stack using one single pointer and an offset... So please ask the interviewer in detail if information hiding is a concern or not...