TL;DR: The phone interviewer was unprepared, interviewed me for the wrong job, gave me conflicting directions, and was unable to identify a working solution to his own interview question.

I first had a phone screen with an HR recruiter. She asked four easy technical questions that didn't really relate to anything in particular (random powers of two, etc.). After waiting for a week, I contacted the company and had to inquire about the next steps. I was then scheduled for a phone interview the following week.

The technical phone interview was frustrating, unpleasant, and cost me the job. I was asked a fairly simple runtime question, which I got correct. I was asked to implement a sorting and searching algorithm in O(N^2) time, which I did. The interviewer then informed me that my answer was incorrect. After politely pointing out that my solution did, in fact, work, I had to wait for him to think it over and finally acknowledge that I was correct.

With less than two minutes remaining, he told me that there was a way to implement it in O(N) time, so my solution was inefficient. Remember, he asked me to implement an O(N^2) algorithm. Upon learning this, I was quickly able to describe in pseudocode how to approach it with a faster runtime, which he told me was correct. He then said thank you and hung up the phone.

One more thing: I was recruited for and interested in the IQE team, but somehow ended up interviewing for the Full Stack Engineer position. I was not notified until shortly before my interview.

Save yourself a bunch of time and skip this company in your job search.

Nothing unexpected. Given an unsorted array, what is the runtime to determine if there are any duplicates?