Amazon Software Development Engineer interview questions

One of the most pathetic interview I have ever had. The interview process was normal. First online assessment, then a phone interview and finally an onsite interview. The first two rounds were easy. Based on DFS and BFS only. But after completion of the second round, I got feedback that my phone interview went well and I was called for an on-site interview. I was asked to give my details to make arrangements for the interview but after that, I didn't get any email. Nearly after 20 days, I got an email from a different HR that I was scheduled a virtual onsite interview. and after a few days, I got another mail that they are deciding to go with another candidate without any explanation. I have given many interviews but this was one of the weirdest and pathetic interview I have ever done.

Applied online to many jobs, got a referral from a current employee and that was the one I got an interview for so I think it helped. First round was an online code challenge, 2 questions in 60 minutes I believe. Passed and got an in-person interview scheduled about 2 weeks later. Company paid for travel and hotel. Interview day was a full afternoon with 4 back-to-back 50-min interviews as interviewers rotated through the conference room. Each interview started with 1-2 "behavioral" questions/discussions that took 10-15 min, and then a technical question for the last 30+ minutes. I had the option to whiteboard code or do it in an online code-sharing UI. I used a mix of both in the interviews. I was also allowed to choose the language I wanted to code in, which was nice. Turnaround was very quick - got an offer 2 days later, then about a week to finalize everything and started within a month.