Three ways to store a graph in memory, advantages and disadvantages

Question

There are three ways to store a graph in memory:

1. Nodes as objects and edges as pointers
2. A matrix containing all edge weights between numbered node x a

Answer 1

A couple more things to consider:

1. The matrix model lends itself more easily to graphs with weighted edges, by storing the weights in the matrix. The object/pointer model would need to store edge weights in a parallel array, which requires synchronization with the pointer array.

2. The object/pointer model works better with directed graphs than undirected graphs because the pointers would need to be maintained in pairs, which can become unsynchronized.