Dariel Solutions Intermediate Software Developer interview questions

Technical interview was set up. It was 2 hours long..with 2 of their developers (1 Senior, 1 Intermediate). Questions are focused on OOP concepts, Data Structures and Algorithms (BigO notations/Complexity), System architecture (MVC), Design Patterns , Databases (SQL). It was very theoretical, more like a discussion. You explain what you understand about these concepts. The interviewers correct you if you confused or mistaken. Questions (that I remember): -What is the difference abstract class and interface -What is the difference between overload and override -Give examples of Design patterns. -Explain what a data structure is -How would you make your solution (to the code challenge) more efficient. -There were questions on SQL, I forgot. -There was a question on Graphs (Hash Tables) Code Challenge: Find the number that repeats an odd number of times in an array. Explain your solution (you don't need to run it, just explain the logic behind it) Just go through your OOP concepts and general Computer Science terms. Know what they are and how they work generally.