Graph implementation adjacency list vs set

Question

After reading about how to implement a graph it seems I have basically two options:

• Matrix
• Adjacency list

In order to decide which implementation to use this post can be useful.

When an adjacency list is used to implement a graph the cost to know if there is an edge between two nodes may take linear time (for those nodes connected to all nodes).

That make me wonder: Why not to use a HashSet instead of a linked list in order to keep the neighbors of a node?

This will give us constant time to know if there is an edge between two nodes. I'm sure must be a disadvantage using a Set instead of Linked list but I can't see it.

Answer 1

I think "list" is just a generic name. I've used a Set and it works perfectly well.

There is no specific reason to use a list instead of a set, here go through this link - Graph using set

Hope this helps!