I was contacted by their in-house recruiter. They were looking for someone with backend and/or frontend knowledge. I had basic knowledge of Python, but my strongest area was Java, which I pointed out on the phone screening. However, the person I talked to said that it didn't matter if I didn't know the language and that knowing the general concepts like data structures, algorithms, etc., was important. They've invited me to an on-site interview.

The on-site interview consisted of five 45-minute interviews with people from different departments. It was really exhausting, especially because they organized the easier ones (HR, cultural fit) at the beginning and the harder ones (Backend, Frontend) at the end. In my opinion, they should have put the technical interviews first.

Technical interviews were not that difficult. There was some database design, some tasks on a whiteboard, and general CS questions. There was one thing that gave me a bad impression. The person interviewing me gave me an assignment to solve on a whiteboard and insisted that I solve it in Python. I asked if I could do it in Java, since that was my strongest language, and they refused. Instead, they told me to write pseudocode, which was pretty weird since they had previously told me that the language didn't matter. But everything else went OK.

They told me that they would get back to me in 2-3 days. After a week, they called me and said that they wouldn't give me an offer because I don't have advanced Python knowledge. That was a surprise to me, since I had been straightforward with them from the beginning regarding my Python knowledge, and at that time, they had told me that it didn't matter.

You have an input array of objects.

Find and return the object from the array which occurs only once.