1. Verify if a given binary tree is a BST. Duplicate values appear towards the left.
2. More like a design question. Given a Piece class and a Side class, design a method solve(pieces[]) which returns a solved puzzle. I had to design the data structure for solved puzzle and how I would write the solve method.

I felt the interview went well, but was rejected without any proper feedback. I also mentioned beforehand that I have seen the BST question and the interviewer was OK with it. :) I have done almost 350+ problems, so these problems were not quite difficult for me. I keep attending mock interviews in https://www.***.com/ (p-r--a-m-p) where almost every feedback is positive, so I am not sure what I did wrong. All the best for your interviews.