Lutron Electronics Project Software Engineer interview questions

I applied online and received an invitation for an interview which did not mention a technical portion. I was given an easy coding problem (given an array of items, filter out duplicates) My solution was O(n) where you’d just put the items in a HashSet. I also gave multiple other solutions and I ended up getting a rejection letter. I’m not sure what exactly is it that they’re looking for.. This was an entry level position. I had work experience and 4.0 GPA and was still rejected. I felt very disrespected during the interview as I was treated like I don’t understand algorithms for some reason.

I talked to Lutron representative at campus career fair. And then next day I had an on campus interview with a tech manager. The interview lasted for less than 40 minutes. It was mainly about my resume and related background information. No made up questions involved. And then the manager shared the recruiting process with me. The interview ended with mine several questions for the manager. There would be a follow up on site interview if this interview went well.