Possible Set representations:

* array (sorted/unsorted) (grow/shrink using realloc)
* linked list (sorted/unsorted) (grow/shrink as usual)
* bitmap  (fixed size = V bits = ceil(V/8) bytes)

Costs           Space     AddEdge   Edge      Outbound  Inbound
                                    Exists?   Edges     Edges

Unsorted Array  V+E       1/d(v)    d(v)      d(v)      E
 
Sorted Array    V+E       d(v)      log(d(v)) d(v)      Vlog(d(v))

Unsorted List   V+E       1         d(v)      d(v)      E

Sorted List     V+E       d(v)      d(v)      d(v)      Vd(v)

Bitmap          V^2       1         1         V         V