Graphs/Java/Adjacency Map Lite

Note: this implementation is more practical for a lightweight problem, such as a programming competition or coding challenge.

Graph class:

• Constructor: initializes list of vertices, list of edges
• Add vertex method (identified by integers)
• Add edge method (takes two integers)

Vertex class:

• Map of Vertex objects to Edge objects, to store connecting edges
• Integer (element/identifier)
• Method: get neighbors
• Method: get element

Edge class:

• List of Vertex objects
• (Optional) int array (element/identifier)
• Constructor: two vertices, set as endpoints
• Method: get endpoints
• Method: get element