Question

What's the topological ordering of the following, and please explain.

A graph with n vertices labeled 0, 1, 2, ..., n-1where each of the vertices from 1 to n-1 has a single outgoing edge that points to vertex 0.

Answer 1

The vertex which has no incoming edges is the one which comes first.

Vertices from 1, 2, ..., n-1 has no incoming edges.
And vertex 0 has incoming edges from 1, 2, ..., n-1

So, We have to visit all 1, 2, ..., n-1 to visit 0 in the topological order.

The topological ordering is
1, 2, ..., n-1, 0