As for the Kevin Bacon Game, data can often be modeled as a graph.

Queries about the data may often be answered by algorithms such as:

• Is vertex x connected to vertex y?
• If so, find a path from a vertex x to vertex y.
• If so, find a shortest path from vertex x to vertex y?
• Is every pair of vertices connected? (That is, is the graph connected?)
• If not connected, how many connected components are there?