Amazon Software Development Engineer interview questions

I contacted Amazon through a job listing. And a person from Amazon contacted me over the phone after 4 days. Initially, the interview seemed very tough, but the interviewer was kind and made me feel comfortable. At first, the job description was given and I was explained my role in the company. Then, there followed a skills test and a technical round

Was scheduled for a phone interview round last week , a week after I applied. The interview started with resume scanning and the interviewer asked questions on my projects, which I answered confidently. Later, I was asked about Linked List, Binary trees. He asked me what big oh notation meant, and the time complexities of linked list and binary trees. I was asked what was the worst case scenario of a Binary Search tree. He then asked me what balanced and unbalanced binary trees were, and asked me to write a code on self balancing binary trees. I have not received a reply about the outcome for the phone interview since last week My perception is that the company looks for applicants who demonstrate a 'can do it attitude' when given a tough problem.