Perform the acyclic-topological sort algorithm on the directed graph having vertex set a-k and
edges
{(j; a);(j; g);(a; b);(a; e);(b; c);(c; k);(d; e);(e; c);(e; f);(e; i);(f; k);
(g; d);(g; e);(g; h);(h; e);(h; i);(i; f);(i; k)}
Show the state of the queue each time it changes state (by either inserting or removing a vertex)