Questions for Marketplace Web Service Engineer
“Write a function for in-order binary tree traversal.”
“Design a restaurant reservation system.”
“Write a function that takes in a list of numbers and returns the number of even numbers in the list.”
Q: Given a database of all the known stars, describe how you would determine the 200 stars closest to
Earth. What is the efficiency of the algorithm you described?
A: Calculate the distance for each star, then select the 200 closest. Although I was able to describe in
English the efficiency of the algorithm (it has to compute the distance to each star once and perform a
sort to get them in order by distance) I wasn't able to tell them off the top of my head what the "Big O"
notation for the algorithm was, after that they seemed to lose interest in the interview.
Here’s a little about Amazon Web Services, taken directly from the Amazon.com Website:
Amazon E-Commerce Service
Amazon E-Commerce Service (ECS) exposes Amazon’s product data and e-commerce
functionality. This allows developers, web site owners and merchants to leverage the data and
functionality that Amazon uses to power its own e-commerce business. ECS 4.0 makes it
extremely easy for developers to build rich, highly effective web sites and applications.
Amazon Elastic Compute Cloud (Amazon EC2) – Limited Beta
Amazon Elastic Compute Cloud (Amazon EC2) is a web service that provides resizable compute
capacity in the cloud. It is designed to make web-scale computing easier for developers.
Just as Amazon Simple Storage Service (Amazon S3) enables storage in the cloud, Amazon EC2
enables “compute” in the cloud. Amazon EC2’s simple web service interface allows you to
obtain and configure capacity with minimal friction. It provides you with complete control of
your computing resources and lets you run on Amazon’s proven computing environment.
Amazon EC2 reduces the time required to obtain and boot new server instances to minutes,
allowing you to quickly scale capacity, both up and down, as your computing requirements
change. Amazon EC2 changes the economics of computing by allowing you to pay only for
capacity that you actually use.
Amazon Historical Pricing
The Amazon Historical Pricing web service gives developers programmatic access to over three
years of actual sales data for books, music, videos, and DVDs (as sold by third-party sellers on
Amazon.com). Sellers can use Amazon Historical Pricing to make informed decisions on pricing
and purchasing.
Amazon Mechanical Turk (Beta)
Amazon Mechanical Turk provides a web services API for computers to integrate Artificial
Artificial Intelligence directly into their processing by making requests of humans. Developers
use the Amazon Mechanical Turk web services API to submit tasks to the Amazon Mechanical
Turk web site, approve completed tasks, and incorporate the answers into their software
applications. To the application, the transaction looks very much like any remote procedure call
– the application sends the request, and the service returns the results. In reality, a network of
humans fuels this Artificial Artificial Intelligence by coming to the web site, searching for and
completing tasks, and receiving payment for their work.
Amazon Simple Storage Service (Amazon S3)
Amazon S3 is storage for the Internet. It is designed to make web-scale computing easier for
developers.
Amazon S3 provides a simple web services interface that can be used to store and retrieve any
amount of data, at any time, from anywhere on the web. It gives any developer access to the
same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to
run its own global network of web sites. The service aims to maximize benefits of scale and to
pass those benefits on to developers.
Amazon Simple Queue Service (Amazon SQS)
Amazon Simple Queue Service (Amazon SQS) offers a reliable, highly scalable hosted queue for
storing messages as they travel between computers. By using Amazon SQS, developers can
simply move data between distributed application components performing different tasks,
without losing messages or requiring each component to be always available.
Amazon SQS works by exposing Amazon’s web-scale messaging infrastructure as a web
service. Any computer on the Internet can add or read messages without any installed software or
special firewall configurations. Components of applications using Amazon SQS can run
independently, and do not need to be on the same network, developed with the same
technologies, or running at the same time.
Alexa Site Thumbnail
The Alexa Site Thumbnail web service provides developers with programmatic access to
thumbnail images for the home pages of web sites. It offers access to Alexa’s large and growing
collection of images, gathered from its comprehensive web crawl.
This web service enables developers to enhance web sites, search results, web directories, blog
entries, and other web real estate with Alexa thumbnail images. Including web site thumbnails
improves user experience by allowing end users to preview sites before clicking on the
thumbnail’s associated link.
Alexa Top Sites
The Alexa Top Sites web service provides access to lists of web sites ordered by Alexa Traffic
Rank. Using the web service developers can understand traffic rankings from the largest to the
smallest sites. The service enables users to page through the list 100 web sites at a time, and by
making multiple requests, to retrieve lists of any size – be it the top 1,000, 5,000, or 100,000 web
sites.
In addition to Alexa Traffic Rank, the information returned for each web site includes the
number of page views the site receives per million users, the average page views per user, and
the number of Alexa users visiting the site.
Alexa Web Information Service (AWIS)
The Alexa Web Information Service makes Alexa’s vast repository of information about the
traffic and structure of the web available to developers.
Service Highlights





Gather information about web sites, including traffic data, contact information, related
links and more.
Access historical traffic data for web sites to analyze growth and understand the effects of
specific events on web site traffic.
Build a web directory into your web site or service using an Alexa enhanced DMOZbased browse service.
Access the list of sites linking to any given site.
Use the Alexa web map to analyze the link structure of the web without the content. Use
the page-to-page links-in and links-out information to invent wholly new search engine
algorithms.
Alexa Web Search
The Alexa Web Search web service offers programmatic access to Alexa’s web search engine.
Developers can use this service to incorporate search results directly into their web sites or
services.
Service Highlights





Comprehensive: Based on 300 Terabytes of Alexa’s web crawl.
Relevant : Advanced relevance algorithms provide highly pertinent search results.
Configurable: Filter search results by passing in over 50 different search fields.
Customizable: Advanced users can build new search index files that can be incorporated
into the Alexa search engine.
Cost-effective: Pay a low rate, and only for what you use.