Version 5.0 The LEDA User Manual

11.17 Sets of Edges ( edge set )
1. Definition
An instance S of the data type edge set is a subset of the edges of a graph G. S is said
to be valid for the edges of G.
#include < LEDA/graph/edge set.h >
2. Creation
edge set
S(const graph& G);
creates an instance S of type edge set valid for all edges currently
in graph G and initializes it to the empty set.
3. Operations
void S.insert(edge x) adds edge x to S.
void S.del(edge x) removes edge x from S.
bool S.member(edge x) returns true if x in S, false otherwise.
edge S.choose( ) returns an edge of S.
int S.size( ) returns the size of S.
bool S.empty( ) returns true iff S is the empty set.
void S.clear( ) makes S the empty set.
4. Implementation
An edge set S for a graph G is implemented by a combination of a list L of edges and an
edge array of list items associating with each edge its position in L. All operations take
constant time, except for clear which takes time O(S). The space requirement is O(n),
where n is the number of edges of G.