Mar 14

Algorithm ends when zeroDegree is empty. 4 vertices not output

  - The algorithm ends when all previous elements in zeroDegree have been
    processed and the list is empty. 
  - However, 4 vertices have not been output.
  - The degrees of these 4 vertices in the degreeOf HashMap are not
    0. 
  - This means a cycle exists among those 4 nodes.

Final Result for Algorithm on this Graph with a Cycle