Undirected Graph Neighborhood Count
Create a public class
GraphCount with a single class method
count accepts two parameters: a
cs1.graphs, and an
You should return the count of the number of nodes in the graph where the number of 2-hop neighbors of that node is
at least as large as the passed
If the passed graph is
null, or if the
int is less than or equal to zero, throw an
What is a 2-hop neighbor? Consider the node B in the following simple unweighted undirected graph:
F | A - B - C - D - E | H | J
B has 4 1-hop neighbors: A, F, C, and H, nodes that are reachable in 1 hop from B. B has 6 2-hop neighbors: A, F, C, H, J, and D, nodes that are reachable in 2 hops from B.
To solve this problem you'll need to write a recursive helper method that you can run starting at each node in the
graph, which you can enumerate using
getNodes() as described below.
Your recursive method will need to keep track of two things as it explores the graph: a set of nodes that
have already been visited, to avoid backtracking, and the distance from the start node.
Your base case can be either reaching a node you have already visited, or reaching 2 hops from the start, at
which point you should stop exploring.
Note that your count will probably be off by one, since you'll probably end up including the start node in your calculation. Be sure to keep that in mind.
This problem is tricky to set up, so we've provided some starter code to get you going. Good luck, and have fun!
cs1.graphs.UnweightedGraph has the following public properties:
cs1.graphs.GraphNode has the following public properties: