Amazon Software Development Engineer, II interview questions

I had telephonic as 1st round. I got rejected there itself :). I have been asked to collabedit few algos. First one is about finding the diameter of a tree. I explained in pseudo-code. I think they are expecting people to do ready-to-use code. 2nd one was to search a word in a large file. I suggest to preprocess the entire file into suffix tree and search. He was not convinced neither do I.. :) because the file was too large to preprocess load into the memory.

A recruiter called and later setup day time for phone interview couple of days later. The phone interview was Ok, little bit of introduction and what I have done in the past, the technical question. He provided a link to web that I can write a program on the fly so he could se what I type.