Each interviewer in my experience has their own special algorithm they love to ask. For instance I was asked a question about the Boyer-Moore majority algorithm

Each interviewer in my experience has their own special algorithm they love to ask. For instance I was asked a question about the Boyer-Moore majority algorithm which is so obscure and rare and hence I messed that interview up. It is usually not the Splay Trees, AVL Trees, Merge Sort it's the logic behind your contextualization of the algo in the problem being asked to be solved