The interviewer was 15 minutes late to the phone interview. Did she even take the interview as seriously as I did?

We started the coding question right away. The interviewer seemed distracted the whole time. There were things dropping, loud thumping, and sudden noise coming from her speaker from time to time. It was very distracting.

The session was not enjoyable or pleasant. I was expected to "autopilot" through the whole thing by myself. The interviewer did not provide any direction as to what to do next. I felt I was conducting the interview instead of being interviewed. I had to ask her if providing an optimized solution was what she wanted me to do next. The whole time was just me talking, and every now and then, I received a "yes," "no," or a short sentence from her. There was no elaboration. I did not sense she was enthusiastic about giving the interview; for the most part, she was silent. I was not sure if she was happy about giving an interview at all.

Toward the end of the 25-minute session, while working on the optimized solution, I asked for guidance. Nothing helpful was given. I struggled until the 30-minute mark. She then called time's up, so it was just a 30-minute interview. She expected me to solve the optimized solution without any help. Of course, she had asked this question many times, so the solution would seem obvious to her. She expected the answer right away. I wouldn't be surprised if she had already written me off much sooner.

Some matrix-related questions