I got invited to the interview because I was participating with a team in a hackathon organized by this company. I had only one round of the interview where I talked to HR and later on talked to my future boss, senior project manager. We discussed my background and potential responsibilities, HR told me about the company. After that for two hours I was solving different logic puzzles and tasks and discussed solutions with senior project manager. My way of thinking and communication skills were the most important aspect of the interview, not right answers. In a few weeks company send me an offer, everyone talked politely.