/usr/include/boost/pending/disjoint_sets.hpp is in libboost1.55-dev 1.55.0+dfsg-3.
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//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
//
#ifndef BOOST_DISJOINT_SETS_HPP
#define BOOST_DISJOINT_SETS_HPP
#include <vector>
#include <boost/graph/properties.hpp>
#include <boost/pending/detail/disjoint_sets.hpp>
namespace boost {
struct find_with_path_halving {
template <class ParentPA, class Vertex>
Vertex operator()(ParentPA p, Vertex v) {
return detail::find_representative_with_path_halving(p, v);
}
};
struct find_with_full_path_compression {
template <class ParentPA, class Vertex>
Vertex operator()(ParentPA p, Vertex v){
return detail::find_representative_with_full_compression(p, v);
}
};
// This is a generalized functor to provide disjoint sets operations
// with "union by rank" and "path compression". A disjoint-set data
// structure maintains a collection S={S1, S2, ..., Sk} of disjoint
// sets. Each set is identified by a representative, which is some
// member of of the set. Sets are represented by rooted trees. Two
// heuristics: "union by rank" and "path compression" are used to
// speed up the operations.
// Disjoint Set requires two vertex properties for internal use. A
// RankPA and a ParentPA. The RankPA must map Vertex to some Integral type
// (preferably the size_type associated with Vertex). The ParentPA
// must map Vertex to Vertex.
template <class RankPA, class ParentPA,
class FindCompress = find_with_full_path_compression
>
class disjoint_sets {
typedef disjoint_sets self;
inline disjoint_sets() {}
public:
inline disjoint_sets(RankPA r, ParentPA p)
: rank(r), parent(p) {}
inline disjoint_sets(const self& c)
: rank(c.rank), parent(c.parent) {}
// Make Set -- Create a singleton set containing vertex x
template <class Element>
inline void make_set(Element x)
{
put(parent, x, x);
typedef typename property_traits<RankPA>::value_type R;
put(rank, x, R());
}
// Link - union the two sets represented by vertex x and y
template <class Element>
inline void link(Element x, Element y)
{
detail::link_sets(parent, rank, x, y, rep);
}
// Union-Set - union the two sets containing vertex x and y
template <class Element>
inline void union_set(Element x, Element y)
{
link(find_set(x), find_set(y));
}
// Find-Set - returns the Element representative of the set
// containing Element x and applies path compression.
template <class Element>
inline Element find_set(Element x)
{
return rep(parent, x);
}
template <class ElementIterator>
inline std::size_t count_sets(ElementIterator first, ElementIterator last)
{
std::size_t count = 0;
for ( ; first != last; ++first)
if (get(parent, *first) == *first)
++count;
return count;
}
template <class ElementIterator>
inline void normalize_sets(ElementIterator first, ElementIterator last)
{
for (; first != last; ++first)
detail::normalize_node(parent, *first);
}
template <class ElementIterator>
inline void compress_sets(ElementIterator first, ElementIterator last)
{
for (; first != last; ++first)
detail::find_representative_with_full_compression(parent, *first);
}
protected:
RankPA rank;
ParentPA parent;
FindCompress rep;
};
template <class ID = identity_property_map,
class InverseID = identity_property_map,
class FindCompress = find_with_full_path_compression
>
class disjoint_sets_with_storage
{
typedef typename property_traits<ID>::value_type Index;
typedef std::vector<Index> ParentContainer;
typedef std::vector<unsigned char> RankContainer;
public:
typedef typename ParentContainer::size_type size_type;
disjoint_sets_with_storage(size_type n = 0,
ID id_ = ID(),
InverseID inv = InverseID())
: id(id_), id_to_vertex(inv), rank(n, 0), parent(n)
{
for (Index i = 0; i < n; ++i)
parent[i] = i;
}
// note this is not normally needed
template <class Element>
inline void
make_set(Element x) {
parent[x] = x;
rank[x] = 0;
}
template <class Element>
inline void
link(Element x, Element y)
{
extend_sets(x,y);
detail::link_sets(&parent[0], &rank[0],
get(id,x), get(id,y), rep);
}
template <class Element>
inline void
union_set(Element x, Element y) {
Element rx = find_set(x);
Element ry = find_set(y);
link(rx, ry);
}
template <class Element>
inline Element find_set(Element x) {
return id_to_vertex[rep(&parent[0], get(id,x))];
}
template <class ElementIterator>
inline std::size_t count_sets(ElementIterator first, ElementIterator last)
{
std::size_t count = 0;
for ( ; first != last; ++first)
if (parent[*first] == *first)
++count;
return count;
}
template <class ElementIterator>
inline void normalize_sets(ElementIterator first, ElementIterator last)
{
for (; first != last; ++first)
detail::normalize_node(&parent[0], *first);
}
template <class ElementIterator>
inline void compress_sets(ElementIterator first, ElementIterator last)
{
for (; first != last; ++first)
detail::find_representative_with_full_compression(&parent[0],
*first);
}
const ParentContainer& parents() { return parent; }
protected:
template <class Element>
inline void
extend_sets(Element x, Element y)
{
Index needed = get(id,x) > get(id,y) ? get(id,x) + 1 : get(id,y) + 1;
if (needed > parent.size()) {
rank.insert(rank.end(), needed - rank.size(), 0);
for (Index k = parent.size(); k < needed; ++k)
parent.push_back(k);
}
}
ID id;
InverseID id_to_vertex;
RankContainer rank;
ParentContainer parent;
FindCompress rep;
};
} // namespace boost
#endif // BOOST_DISJOINT_SETS_HPP
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