dotdigital .NET Developer interview questions

I applied directly on their website. The interview process was about 3 weeks from first screen call from HR to Final interview. after the screening call was an online assessment asking you to write a solution that determines the minimum average of 3 consecutive number in an array. If you pass the online assessment, you proceed to the final interview with a senior dev and one of the team leads. The questions were basic such as what is the difference between an abstract class and an interface. The second half of the final interview is a code session where you are asked to build a calculator that takes a single string input e.g. "5+5"