A graph consists of a set of vertices connected together by a set of edges. A tree is a special type of graph. In this example, a vertex is a node of that tree, and an edge is a link between a parent and one of it's children.
Write a function that determines if a path exists between two vertices of a graph.
The graph will be represented as an object, each of whose keys represents a vertex of the graph and whose value represents all vertices that can be reached from the aforementioned key. In the example below, there is a connection from vertex
a to vertex
b and a connection from vertex
b to vertices
d but not a connection from vertex
b to vertex