January 2011 Engine Yard Ruby Puzzle

ride4ruby.rb

require 'net/http'
require 'rexml/document'

states = ["Alabama", "Alaska", "Arizona", "Arkansas", "California", "Colorado", "Connecticut", "Delaware", "District of Columbia", "Florida", "Georgia", "Idaho", "Illinois", "Indiana", "Iowa", "Kansas", "Kentucky", "Louisiana", "Maine", "Maryland", "Massachusetts", "Michigan", "Minnesota", "Mississippi", "Missouri", "Montana", "Nebraska", "Nevada", "New Hampshire", "New Jersey", "New Mexico", "New York", "North Carolina", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota", "Tennessee", "Texas", "Utah", "Vermont", "Virginia", "Washington", "West Virginia", "Wisconsin", "Wyoming"]

map_key = "#{YOUR GOOGLE MAP API KEY}"

Position = Struct.new(:address, :latitude, :longitude)
western_most = Position.new("", 0.0, 180.0)
eastern_most = Position.new("", 0.0, -180.0)

states.each do |state|
  cities_url = "http://maps.google.com/maps/geo?q=#{URI.escape state}%20Ruby%20Street&output=xml&key=#{map_key}"
  xml_data = Net::HTTP.get_response(URI.parse(cities_url)).body
  doc = REXML::Document.new(xml_data)

  doc.elements.each("kml/Response/Placemark") do |place| 
    next unless place.elements["AddressDetails/Country/CountryNameCode"].text == "US"
    coord = place.elements["Point/coordinates"].text.split ',' 
    position = Position.new(place.elements["address"].text, Float(coord[1]), Float(coord[0]))
    western_most = position if position.longitude < western_most.longitude
    eastern_most = position if position.longitude > eastern_most.longitude
  end 
end

directions_url = "http://maps.google.com/maps/api/directions/xml?origin=#{eastern_most.latitude},#{eastern_most.longitude}&destination=#{western_most.latitude},#{western_most.longitude}&sensor=false&key=#{map_key}"
xml_data = Net::HTTP.get_response(URI.parse(directions_url)).body
doc = REXML::Document.new(xml_data)
doc.elements.each("DirectionsResponse/route/leg/distance/text") do |distance| 
  puts "Eastern most address is #{eastern_most.address} and western most address is #{western_most.address} and distance between them is #{distance.text}"
end