DeleteEdge: remove tail from parent list of head vertex

[svrana]

Makes DeleteEdge the inverse of AddEdge

Description

AddEdge updates the children and parents set of the head and tail vertex, while DeleteEdge only removes the edge from the children of the tail vertex. This makes it difficult to use DeleteEdge as it does not fully remove the edge from the dag. In order to implement a topological sort, I needed to first implement my own DeleteEdge which shouldn't be necessary.

Approach

Fix the glitch by updating the parent list of the headVertex.

I followed the existing code in DeleteEdge that searches the entire set before calling remove(), but this is redundant as OrderedSet will repeat the same operation afaict. I can adjust that if desired.

[Druid33]

Hi,

i see this PR wait over 2 years to merge. Is this package still supported or not?
I used it in one project and found bug on removing Vertex. I thing about make bugfix, but if package is dead, its useless.