  In this paper, we study the problem of fast dynamic pointer following: given
a directed graph $G$ where each vertex has outdegree $1$, efficiently support
the operations of i) changing the outgoing edge of any vertex, and ii) find the
vertex $k$ vertices `after' a given vertex. We exhibit a solution to this
problem based on link-cut trees that requires $O(\lg n)$ time per operation,
and prove that this is optimal in the cell-probe complexity model.
