HERE Technologies interview questions

Had two rounds, One phone call and another onsite . Phone call was with the Director of Engineering, rapid fire interview ( simple output coding(google docs) a lot of basic math, OOPs, design patterns, Core c++, Application design ( front end to back end). They just test your depth of knowledge. It is okay if you don't answer everything if you have never worked with them ( I am new grad(master student) and really young) . Heard back from them within a week to come over for a onsite interview. Onsite Interview. Lunch with Team. Then i think it was a really long interview from 1 to 4:30pm Follow up with director for 2 hours. They asked a lot of questions again from the same domain. I guess its just to test your adaptability to stress and how you answer at that moment. I didn't know many concepts in Cpp or OOPs but they try to give me hints as i was inexperienced. Two 3D Math questions, 2 coding questions( one dynamic and another just string reversal) and alot of OOPs and Cpp trick questions , design patterns etc. I managed to answer most of them , but i could see one interviewer losing his patience , coz i was not familar or didn't understand many topics they asked.( I guess my inexperience was shown there) , There was also an old engineer who was being interviewed. I guess the director really liked me, but i guess my inexperience was really obvious inspite of me answering most of them. All intelligent engineers work there but i guess they should have put into consideration that i was inexperienced and not promoted my onsite from a software engineer to a senior software engineer. They asked me dates for an internship instead of a fulltime, but later the director told me the HR had difficulty approving it. It was really bad on their part to keep me waiting/ emailing back really late and they told me that are sorry and that they would consider me for a summer internship but i have not heard from them since so i think i should consider it as a no and move on. In spite of other job offers , i wanted to work on their team , because their work seemed really interesting, so i declined all others i got from more bigger players etc. I have also not received travel reimbursement from them for the interview which i was promised. Engineers, Director and all are great, the work seems great but it just didn't work out. It's okay it worked out in the end because i am joining another great company that is offering me really competitive job offer and i think i will be joining them.