Basically, a graph is a data structure that's able to represent relations in a collection of objects. Under this paradigm, the objects are the graph's nodes and the relations are the graph's links (or edges). The graph is directed if the links have an orientation (conceptually, they're like the one-way streets of a city); otherwise, the graph is undirected. In the following table, examples of well-known graphs are provided:
|
Graph example |
Type |
Nodes |
Edges |
|
World Wide Web |
Directed |
Web pages |
Links |
|
|
Undirected |
People |
Friendship |
|
|
Directed |
People |
Follower |
|
IP network |
Undirected |
Hosts |
Wires/Connections |
|
Navigation systems |
Directed |
Places/Addresses ... |
