An outsider recruiter contacted me first, then transferred me to an in-house recruiter. Then came the phone interview.

I had a terrible experience with Zillow. The message they sent to applicants was: "We are paying really well in this town. You are lucky to be here."

And it showed:

• The outsider recruiter was super eager and overselling.
• The in-house recruiter couldn't care less, always late. They canceled the first contact at the last minute, then were 15 minutes late for the second.
• The phone interviewer dropped the ball, not calling until 30 minutes into a hour-long appointment.

I suggested we cancel and reschedule, but they nudged me into "something quick, let's see where we end up." Then they proceeded with a 3-dimensional clustering question.

You are given a list of three-dimensional coordinates. Find the point that is at the center.