Tesco interview questions

I got a call a few weeks after I applied online. I was told about the company and what the team is made up of. I was asked simple questions and I was told I will be invited for a technical interview soon. I got a call after about 4weeks to schedule a time for the technical interview. I was asked to write a programme to find a number in a Fibonacci sequence. After that I was asked questions along my expertise in optimisation. Examples of minimisation and maximisation problems, how I would solve dynamic problems. I gave examples of real problems I have worked on in the past. They seemed happy with how I answered the questions. I didn't hear again from them until another month where I got a call saying I passed but the position has been filled.