Ocado Group Software Engineer interview questions

I was put on to Ocado's interview from a recruiter. The first stage was to complete an online Codility.com test (3 tests). You can choose in the tool which programming language you'd like to use. (c++, java, etc.. there's quite a few). The questions weren't trivial. The first was somewhat similar to how you might program mode or median, however #2 and #3 were more difficult. #2 invoved finding a particular sequence in an array and #3 involved finding a sum of specific values in a matrix. I ran out of time on this 3rd question, but put in the headers of the functions so that they could see what I was going to write.. this seemed adequate. (As a side note, the recruier had told me that the tests would be find the mean, mode and median, so I was a little surprised how much more difficult it was when I went to do it. So beware they do seem to change the codility questions.) I got through to the next round, which involved going to the HQ (Hatfield). They sit you in a room with the other candidates and you sit 2 tests (paper). The first is using a made-up language which is somewhat like assembly, but not as difficult. You have to complete (fill-in) functions, which create other functions (might be 'greater than' for example) which you can then use in subsequent questions. The second test is just a simple java test involving a linked-list. Insertion/removal/reversal. etc. If you get through that stage they take you on a tour of the factory (quite impressive). After that you have a chat with a manager. Then you go home. Then if you get through you have to go in again for the 'final round', whereby you have a chat with 2 managers, then 1 manager. (heads of the different departments). The first chat you might have to write some code on the white board. (I had a disagreement with one of them about object-orientation during this stage, see the end of this text..) After that you go home. Then finally you get told that after passing all these tests that you're not a good technical fit. As I partially commented on with the manager, it seems that Ocado have some kind of problem with their recruitment. They say they can't find good people (they are opening an office in Poland due to this), however it's evident having gone through the process that they don't know what they're looking for, or what they're looking for is unrealistic. The fact that they have "interview days" every Friday and the fact that all these people that have passed their tests and have good backgrounds don't get offers should be ringing alarm bells for someone there. Ocado are mostly a Java shop (minor c# also) as well as web. The people there all seemed nice (apart from one guy that was a pedant and seemed to think that object orientation was inherently "better" (even with everything as 'public') than a non-OO solution for a very simple problem, despite my reasoned arguments to the contrary. Also, they seemed overly obsessed with questions about threading and synchronisation. ) I would be wary of going for an interview with Ocado as I suspect you will be wasting your time. Then again, you might be just the the Ocadoclone they're looking for.

After completing an online skills questionnaire, was invited to attend an assessment centre. The centre consists two separate logic and Java programming tests. Interviews then conducted if successful; usually on a later date but this can be arranged on the same day if coming from further afield. Undertook a technical interview, including presenting understanding of basic algorithms and data structures, followed by two interviews with senior management.