Edge list
An array of pairs of vertex numbers. A third number can be added to represent weighted edges.
[ [0,1], [0,6], [0,8], [1,4], [1,6], [1,9], [2,4], [2,6], [3,4] ]
Adjacency list
For each vertex i, store an array of the vertices adjacent to it.
Adjacency map
Similar to an adjacency list except the list of neighbors is stored in a hash table instead of an array. This has much better performance than an adjacency list.
Adjacency matrix
Two dimensional array that tells you whether an edge between vertexes.
This isn’t the most space efficient. So adjacency lists & adjacency maps are more practical in the real world.
