TIAA Java Backend Developer interview questions

First round was ok, mostly theory kind questions like what is JVM what is classloader different types of compilers what is byte code etc mostly straight forward questions. Second interviewer was acting too smart, he gave me a problem which is np complete and then he twiked a condition in the problem which according to him will make it solvable, and then I started my questions about the problem and came up with multiple scenarios where his little twik will fail, which may have hurted his ego, and he said I am not solving problem correctly I am thinking about too many scenrios which according to him is not good. For the record when we approach problem we first take a sample case and see how we can solve that problem manually then we device an algorithm to solve the problem. When we select sample there are few cases which we need to ask to the person who gave us the problem and it is expected that that person should be able to respond to all the answers. And asking more questions about the problem is actually a good sign that the person who is trying to solve a problem is not focusing on one aspect only. This is how we solve problem. I think something opposite is happening in TIAA interviews apparently....:D