Index: biconnected_components.hpp
===================================================================
RCS file: /cvsroot/boost/boost/boost/graph/biconnected_components.hpp,v
retrieving revision 1.9
diff -b -u -2 -r1.9 biconnected_components.hpp
--- biconnected_components.hpp 3 Nov 2004 15:40:09 -0000 1.9
+++ biconnected_components.hpp 19 Feb 2005 22:23:24 -0000
@@ -19,4 +19,6 @@
#include <boost/graph/graph_concepts.hpp>
#include <boost/property_map.hpp>
+#include <boost/graph/depth_first_search.hpp>
+#include <boost/graph/graph_utility.hpp>
namespace boost
@@ -24,42 +26,90 @@
namespace detail
{
- template <typename Graph, typename ComponentMap, typename DiscoverTimeMap,
- typename LowPointMap, typename OutputIterator, typename Stack>
- OutputIterator
- biconnect(typename graph_traits < Graph >::vertex_descriptor v,
- typename graph_traits < Graph >::vertex_descriptor u,
- bool at_top,
- const Graph & g,
+ template <typename ComponentMap, typename DiscoverTimeMap,
+ typename LowPointMap, typename PredecessorMap,
+ typename OutputIterator, typename Stack>
+ struct biconnected_components_visitor : public dfs_visitor<>
+ {
+ biconnected_components_visitor(
ComponentMap comp,
- std::size_t & c,
- DiscoverTimeMap d,
- std::size_t & dfs_time, LowPointMap lowpt,
+ std::size_t& c,
+ DiscoverTimeMap dtm,
+ std::size_t& dfs_time,
+ LowPointMap lowpt,
+ PredecessorMap pred,
OutputIterator out,
- Stack & S)
+ Stack& S) :
+ comp(comp),
+ c(c),
+ dtm(dtm),
+ dfs_time(dfs_time),
+ lowpt(lowpt),
+ pred(pred),
+ out(out),
+ S(S) { }
+
+ template <typename Vertex, typename Graph>
+ void start_vertex(const Vertex& u, Graph&)
+ {
+ put(pred, u, u);
+ }
+
+ template <typename Vertex, typename Graph>
+ void discover_vertex(const Vertex& u, Graph&)
+ {
+ put(dtm, u, ++dfs_time);
+ put(lowpt, u, get(dtm, u));
+ }
+
+ template <typename Edge, typename Graph>
+ void tree_edge(const Edge& e, Graph& g)
+ {
+ S.push(e);
+ put(pred, target(e, g), source(e, g));
+ }
+
+ template <typename Edge, typename Graph>
+ void back_edge(const Edge& e, Graph& g)
{
BOOST_USING_STD_MIN();
- typedef typename graph_traits < Graph >::vertex_descriptor vertex_t;
- typedef typename property_traits < DiscoverTimeMap >::value_type D;
- D infinity = (std::numeric_limits < D >::max)();
- put(d, v, ++dfs_time);
- put(lowpt, v, get(d, v));
+ if ( target(e, g) != get(pred, source(e, g)) )
+ {
+ S.push(e);
+ put(lowpt, source(e, g), min BOOST_PREVENT_MACRO_SUBSTITUTION(
+ get(lowpt, source(e, g)), get(dtm, target(e, g))));
+ }
+ }
+
+ template <typename Vertex, typename Graph>
+ void finish_vertex(const Vertex& u, Graph& g)
+ {
+ BOOST_USING_STD_MIN();
+ Vertex parent = get(pred, u);
bool is_art_point = false;
- std::size_t visited_children = 0;
- typename graph_traits < Graph >::out_edge_iterator ei, ei_end;
- for (tie(ei, ei_end) = out_edges(v, g); ei != ei_end; ++ei)
- {
- vertex_t w = target(*ei, g);
- if (get(d, w) == infinity)
- {
- ++visited_children;
- S.push(*ei);
- out = biconnect(w, v, false, g, comp, c, d, dfs_time, lowpt, out, S);
- put(lowpt, v, min BOOST_PREVENT_MACRO_SUBSTITUTION(get(lowpt, v), get(lowpt, w)));
- if (get(lowpt, w) >= get(d, v))
+ if ( get(dtm, parent) > get(dtm, u) )
+ {
+ parent = get(pred, parent);
+ is_art_point = true;
+ }
+ if ( parent == u ) // at top
+ {
+ if ( get(dtm, u) + 1 == get(dtm, get(pred, u)) )
+ is_art_point = false;
+ }
+ else
{
- if (!at_top) is_art_point = true;
+ put(lowpt, parent, min BOOST_PREVENT_MACRO_SUBSTITUTION(get(lowpt, parent), get(lowpt, u)));
+
+ if (get(lowpt, u) >= get(dtm, parent))
+ {
+ if ( get(dtm, parent) > get(dtm, get(pred, parent)) )
+ {
+ put(pred, u, get(pred, parent));
+ put(pred, parent, u);
+ }
- while (d[source(S.top(), g)] >= d[w]) {
+ while ( get(dtm, source(S.top(), g)) >= get(dtm, u) )
+ {
put(comp, S.top(), c);
S.pop();
@@ -68,29 +118,32 @@
S.pop();
++c;
-
- }
- } else if (get(d, w) < get(d, v) && (!at_top && w != u))
+ if ( S.empty() )
{
- S.push(*ei);
- put(lowpt, v, min BOOST_PREVENT_MACRO_SUBSTITUTION(get(lowpt, v), get(d, w)));
+ put(pred, u, parent);
+ put(pred, parent, u);
}
}
-
- if (at_top && visited_children > 1)
- is_art_point = true;
- if (is_art_point)
- *out++ = v;
-
- return out;
}
-
+ if ( is_art_point )
+ *out++ = u;
}
+ ComponentMap comp;
+ std::size_t& c;
+ DiscoverTimeMap dtm;
+ std::size_t& dfs_time;
+ LowPointMap lowpt;
+ PredecessorMap pred;
+ OutputIterator out;
+ Stack& S;
+
+ };
+ } // namespace detail
+
template<typename Graph, typename ComponentMap, typename OutputIterator,
- typename DiscoverTimeMap, typename LowPointMap >
+ typename DiscoverTimeMap, typename LowPointMap, typename PredecessorMap>
std::pair<std::size_t, OutputIterator>
- biconnected_components(const Graph & g, ComponentMap comp,
- OutputIterator out, DiscoverTimeMap discover_time,
- LowPointMap lowpt)
+ biconnected_components(const Graph & g, ComponentMap comp, OutputIterator out,
+ DiscoverTimeMap discover_time, LowPointMap lowpt, PredecessorMap pred)
{
typedef typename graph_traits < Graph >::vertex_descriptor vertex_t;
@@ -104,20 +157,35 @@
function_requires < ReadWritePropertyMapConcept < LowPointMap,
vertex_t > >();
+ function_requires < ReadWritePropertyMapConcept < PredecessorMap,
+ vertex_t > >();
- typedef typename property_traits < DiscoverTimeMap >::value_type D;
std::size_t num_components = 0;
std::size_t dfs_time = 0;
std::stack < edge_t > S;
- typename graph_traits < Graph >::vertex_iterator wi, wi_end;
- std::size_t infinity = (std::numeric_limits < std::size_t >::max)();
- for (tie(wi, wi_end) = vertices(g); wi != wi_end; ++wi)
- put(discover_time, *wi, infinity);
-
- for (tie(wi, wi_end) = vertices(g); wi != wi_end; ++wi)
- if (get(discover_time, *wi) == (std::numeric_limits < D >::max)())
- out = detail::biconnect(*wi, *wi, true, g, comp, num_components,
- discover_time, dfs_time, lowpt, out, S);
- return std::pair<std::size_t, OutputIterator>(num_components, out);
+ detail::biconnected_components_visitor<ComponentMap, DiscoverTimeMap,
+ iterator_property_map<typename std::vector<vertex_t>::iterator,
+ typename property_map<Graph, vertex_index_t>::type, vertex_t, vertex_t&>,
+ LowPointMap, OutputIterator, std::stack<edge_t> >
+ vis(comp, num_components, discover_time, dfs_time,
+ lowpt, pred, out, S);
+
+ depth_first_search(g, visitor(vis));
+
+ return std::pair<std::size_t, OutputIterator>(num_components, vis.out);
+ }
+
+ template<typename Graph, typename ComponentMap, typename OutputIterator,
+ typename DiscoverTimeMap, typename LowPointMap >
+ std::pair<std::size_t, OutputIterator>
+ biconnected_components(const Graph & g, ComponentMap comp,
+ OutputIterator out, DiscoverTimeMap discover_time,
+ LowPointMap lowpt)
+ {
+ typedef typename graph_traits<Graph>::vertex_descriptor vertex_t;
+ std::vector<vertex_t> pred(num_vertices(g));
+
+ return biconnected_components(g, comp, out, discover_time, lowpt,
+ make_iterator_property_map(pred.begin(), get(vertex_index, g)));
}