Amazon Sr. Manager Software Development interview questions

Interviews in Bangalore office never follows the guideline as advertized in the website. There were no telephonic interviews at all and a mere single round of face to face interview for a senior position. Just 3 questions of which one was about yourself and 2 design questions that too at an algorithmic level. 1. For a set of streaming numbers (maybe billions) design a data structure to compute sum, average and median. 2. Design an Instant Messaging system at a high level including the possible number of servers for around 10 million users. The features include buddy list and presence updates. Also an opinion was formed that iPhone SDK does not support C++. The organization should definitely refine the process considering the fact that a single opinion is normally not considered good enough to hire senior professionals.