Amazon Software Development Engineer interview questions

I applied online and was contacted by Amazon.com for online assessment. This was 90 mins coding assessment. After one week , they told me to again take another personality online assessment. Two weeks later they invited me for on-site interview. They arranged everything from travel to accommodation. In on-site I had back to back 3 technical (coding) interviews on white board. I was supposed to have 4 interviews but one of my interviewer was not able to make it so they told me that I will be having that part as phone interview later.