Algorithm to find lowest common ancestor in directed acyclic graph?

Question

Imagine a directed acyclic graph as follows, where:

• \"A\" is the root (there is always exactly one root)
• each node knows its parent(s)
• the no

Answer 1

I was looking for a solution to the same problem and I found a solution in the following paper:

http://dx.doi.org/10.1016/j.ipl.2010.02.014

In short, you are not looking for the lowest common ancestor, but for the lowest SINGLE common ancestor, which they define in this paper.