I applied through an outsourced recruiter. # First step: call with the recuirter about my experience and background. # Second step: technical interview with a team leader consisted of: - 20 min of Java technical questions (not too hard). - 40 min of Codility exercise (not too complex). # Third step: onsite interview divided in 4 stages: - aptitude test: 13 logical exercises to be solved in Assembly-like language (1 hour). - behavioral interview: questions about several situations you had to deal with and how you managed them along your professional career. (1 hour) - pair programming: 1. Finding a solution for a problem and coding it: a project was left incompleted and your task is to complete the missing parts. Your pair (a senior developer who is seated beside you) guides you to the solution they want to you to go (if you are able to figure it out). After that is asked you to improve the code which implies deep knowledge of Java data structures implementations, sorting and searching algorithms. All of this while you were being observed by a 2 team leaders who were evaluating you. The problem was: given a set of million data points (coordinates) represented by two values (x and y) you must determine which of those data points are inside the area described by a rectangle (x1, x2, y1, y2). My first idea was to iterate over all data points and pick up data points contained in the rectangle area then I was asked for a more efficient solution. I proposed a solution that I thought it could work but we went with a "quad tree" solution, which I had never heard before. 2. Java Questions about data structures, threading and other topics. It took 2 hours and was very stressful because I felt very under pressure and observed. - soft skill: general questions about your past working experience and future goals. (1 hour) I did not get an offer because I didn't pass pair programming. Apparently my tech skills were below their expectations. The recruiter and the interviewers at Ocado were very friendly. They treated me in very kindle and professional way. I would recommand Ocado as place to work.

I don't remember every aspect of that interview well, but I know there were a few deep-level questions about how data structures work. Interview was conducted by two devs. It seemed formal and the atmosphere was rough.