Version 5.0 The LEDA User Manual

6.15 Dynamic Collections of Trees ( tree collection )
1. Definition
An instance D of the parameterized data type tree collection is a collection of vertex
disjoint rooted trees, each of whose vertices has a double-valued cost and contains an
information of type I, called the information type of D.
#include < LEDA/core/tree collection.h >
2. Creation
tree collection D;
creates an instance D of type tree collection, initialized with the
empty collection.
3. Operations
d vertex D.maketree(I x) adds a new tree to D containing a single vertex v
with cost zero and information x, and returns v.
const I& D.inf(d vertex v) returns the information of vertex v.
d vertex D.findroot(d vertex v) returns the root of the tree containing v.
d vertex D.findcost(d vertex v, double& x)
sets x to the minimum cost of a vertex on the tree
path from v to findroot(v) and returns the last
vertex (closest to the root) on this path of cost x.
d vertex D.parent(d vertex v) returns the parent vertex of v.
void D.addcost(d vertex v, double x)
void D.link(d vertex v, d vertex x)
adds double number x to the cost of every vertex
on the tree path from v to findroot(v).
combines the trees containing vertices v and w by
adding the edge (v, w). (We regard tree edges as
directed from child to parent.)
Precondition: v and w are in different trees and v
is a root.
void D.cut(d vertex v) divides the tree containing vertex v into two trees
by deleting the edge out of v.
Precondition: v is not a tree root.