private void Add(PathEdge e)
{
int u = e.Either();
int v = e.Other(u);
Add(u, v, e);
}
/// <summary>
/// Add a path-edge to the path-graph. Edges are only added to the vertex of
/// lowest rank (see. constructor).
/// </summary>
/// <param name="edge">path edge</param>
private void Add(PathEdge edge)
{
int u = edge.Either();
int v = edge.Other(u);
if (rank[u] < rank[v])
{
graph[u].Add(edge);
}
else
{
graph[v].Add(edge);
}
}