// (C) Copyright Jeremy Siek 2004 | |
// 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_DETAIL_DISJOINT_SETS_HPP | |
#define BOOST_DETAIL_DISJOINT_SETS_HPP | |
namespace boost { | |
namespace detail { | |
template <class ParentPA, class Vertex> | |
Vertex | |
find_representative_with_path_halving(ParentPA p, Vertex v) | |
{ | |
Vertex parent = get(p, v); | |
Vertex grandparent = get(p, parent); | |
while (parent != grandparent) { | |
put(p, v, grandparent); | |
v = grandparent; | |
parent = get(p, v); | |
grandparent = get(p, parent); | |
} | |
return parent; | |
} | |
template <class ParentPA, class Vertex> | |
Vertex | |
find_representative_with_full_compression(ParentPA parent, Vertex v) | |
{ | |
Vertex old = v; | |
Vertex ancestor = get(parent, v); | |
while (ancestor != v) { | |
v = ancestor; | |
ancestor = get(parent, v); | |
} | |
v = get(parent, old); | |
while (ancestor != v) { | |
put(parent, old, ancestor); | |
old = v; | |
v = get(parent, old); | |
} | |
return ancestor; | |
} | |
/* the postcondition of link sets is: | |
component_representative(i) == component_representative(j) | |
*/ | |
template <class ParentPA, class RankPA, class Vertex, | |
class ComponentRepresentative> | |
inline void | |
link_sets(ParentPA p, RankPA rank, Vertex i, Vertex j, | |
ComponentRepresentative comp_rep) | |
{ | |
i = comp_rep(p, i); | |
j = comp_rep(p, j); | |
if (i == j) return; | |
if (get(rank, i) > get(rank, j)) | |
put(p, j, i); | |
else { | |
put(p, i, j); | |
if (get(rank, i) == get(rank, j)) | |
put(rank, j, get(rank, j) + 1); | |
} | |
} | |
// normalize components has the following postcondidition: | |
// i >= p[i] | |
// that is, the representative is the node with the smallest index in its class | |
// as its precondition it it assumes that the node container is compressed | |
template <class ParentPA, class Vertex> | |
inline void | |
normalize_node(ParentPA p, Vertex i) | |
{ | |
if (i > get(p,i) || get(p, get(p,i)) != get(p,i)) | |
put(p,i, get(p, get(p,i))); | |
else { | |
put(p, get(p,i), i); | |
put(p, i, i); | |
} | |
} | |
} // namespace detail | |
} // namespace boost | |
#endif // BOOST_DETAIL_DISJOINT_SETS_HPP |