Amazon Software Engineer interview questions

I got a phone call for HR interview. They asked about team skills, basic skills acquired during project. The technical interview consisted of the following: check if palindrome tree stack and cue hash table

I applied through a HR and then I had two 45 minutes phone interviews back to back. Both of the phone interviews were extremely technical and required you to code on google docs. In the beginning of both interviews, I was asked simple technical questions like what is hashtable and linked list and basic data structure questions. I screwed up coding part for both my interviews.