Summary

A graph has vertices and edges. Graphs can be directed_graph or undirected_graph, and may be a weighted_graph. Important terms: vertex_degree, path, and cycle. A connected_graph lets every vertex reach another. Store graphs as an adjacency_list or an adjacency_matrix. Common examples are social_networks, road_maps, and web_links. A tree is an acyclic connected_graph. A dag has no directed cycles. Some graphs allow a self_loop or are a multigraph.