In a directed graph, G represented as E(u,v), where u->v is an edge in the graph. You can find your universal sink by the following algorithm :
-> Iterate over each edge E(u,v) belonging in the graph G. For each edge E(u,v) you visit, increment the in-degree for v by one.
-> Iterate on all vertexes, and check for the one with in-degree V-1.
After doing these 2 simple loops. You will have only one or no vertex with you.
In case you have no vertex with V-1 as in-degree, then there is no universal sink.
Else your have your universal sink.
