
edge
    start vertex
    end vertex


+---------+  +--------+--------+---------------------------------------
|      ptr|->| edge 1 | edge 2 | ...
|     used|  +--------+--------+--------------------------------------
|allocated|     |
|   sorted|     V
|maxEdgeID|    +----------------+
+---------+    | variable field | 
|    .    |    +----------------+
|    .    |
|    .    |
+---------+
|         |
|         |
|         |
|         |
|         |
+---------+
