Cities Are Connected
Create a public class
Connections with a single public constructor that accepts a
String contains, in CSV format, a list of cities and other cities that they are connected to.
So, for example, the input:
Means that Champaign is connected to Chicago and St. Louis, and that Chicago is connected to Detroit and
Milwaukee, and so on.
Essentially the CSV serializes a directed graph, where the first item on each line is a node and the other items
represent other nodes that it is connected to.
This is one way of serializing a directed, unweighted graph.
String passed to the constructor is
null, throw an
Make sure to
trim all the
Strings that you extract from the CSV.
Your class should parse this
String and provide a single instance method
isConnected accepts two
Strings and returns
true if the first city is connected to the second based on the
graph passed to the constructor.
So, given the input above,
isConnected("Champaign", "Chicago") would return
isConnected("Chicago", "Champaign") would return
(Note that the graph is not necessarily symmetric.)
String passed to
null, or if you don't have connection information for the source,
you should throw an
Note that only the cities that appear first on each line in the CSV should be treated as cities you have
connection information for.
So, for example, even though "Detroit" appears as a destination from "Chicago" in the data set above, we do not
have a line starting with "Detroit", and therefore a call to
isConnected with "Detroit" as the first parameter
should throw an
Our suggestion is to use a private field to store a data structure that you populate in your constructor.
This will keep your
isConnected method simpler.
Good luck, and have fun!