Big Oh Notation Software Developer interview questions

Consist of 3 rounds: 1. HR 2. Technical round with senior. 3. Technical round with CEO. With Senior it was problem solving round, like given an array, find out the word which contains particular character. With CEO it was general mobile questions on how to track memory leaks, what is ARC and how it works, etc. Interview was good but the environment is stressed while working.

firstly you should have to clear pen paper test then further interview process start. In pen paper test they ask two coding question then after completion of both the questions they ask one oops question