Fix wrong iteration in ListGraph snapshot, part II. (#598)
1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
3 * This file is a part of LEMON, a generic C++ optimization library.
5 * Copyright (C) 2003-2013
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
19 #ifndef LEMON_KRUSKAL_H
20 #define LEMON_KRUSKAL_H
24 #include <lemon/unionfind.h>
25 #include <lemon/maps.h>
27 #include <lemon/core.h>
28 #include <lemon/bits/traits.h>
32 ///\brief Kruskal's algorithm to compute a minimum cost spanning tree
36 namespace _kruskal_bits {
38 // Kruskal for directed graphs.
40 template <typename Digraph, typename In, typename Out>
41 typename disable_if<lemon::UndirectedTagIndicator<Digraph>,
42 typename In::value_type::second_type >::type
43 kruskal(const Digraph& digraph, const In& in, Out& out,dummy<0> = 0) {
44 typedef typename In::value_type::second_type Value;
45 typedef typename Digraph::template NodeMap<int> IndexMap;
46 typedef typename Digraph::Node Node;
48 IndexMap index(digraph);
49 UnionFind<IndexMap> uf(index);
50 for (typename Digraph::NodeIt it(digraph); it != INVALID; ++it) {
55 for (typename In::const_iterator it = in.begin(); it != in.end(); ++it) {
56 if (uf.join(digraph.target(it->first),digraph.source(it->first))) {
57 out.set(it->first, true);
58 tree_value += it->second;
61 out.set(it->first, false);
67 // Kruskal for undirected graphs.
69 template <typename Graph, typename In, typename Out>
70 typename enable_if<lemon::UndirectedTagIndicator<Graph>,
71 typename In::value_type::second_type >::type
72 kruskal(const Graph& graph, const In& in, Out& out,dummy<1> = 1) {
73 typedef typename In::value_type::second_type Value;
74 typedef typename Graph::template NodeMap<int> IndexMap;
75 typedef typename Graph::Node Node;
77 IndexMap index(graph);
78 UnionFind<IndexMap> uf(index);
79 for (typename Graph::NodeIt it(graph); it != INVALID; ++it) {
84 for (typename In::const_iterator it = in.begin(); it != in.end(); ++it) {
85 if (uf.join(graph.u(it->first),graph.v(it->first))) {
86 out.set(it->first, true);
87 tree_value += it->second;
90 out.set(it->first, false);
97 template <typename Sequence>
99 typedef typename Sequence::value_type Value;
100 bool operator()(const Value& left, const Value& right) {
101 return left.second < right.second;
105 template <typename In, typename Enable = void>
106 struct SequenceInputIndicator {
107 static const bool value = false;
110 template <typename In>
111 struct SequenceInputIndicator<In,
112 typename exists<typename In::value_type::first_type>::type> {
113 static const bool value = true;
116 template <typename In, typename Enable = void>
117 struct MapInputIndicator {
118 static const bool value = false;
121 template <typename In>
122 struct MapInputIndicator<In,
123 typename exists<typename In::Value>::type> {
124 static const bool value = true;
127 template <typename In, typename Enable = void>
128 struct SequenceOutputIndicator {
129 static const bool value = false;
132 template <typename Out>
133 struct SequenceOutputIndicator<Out,
134 typename exists<typename Out::value_type>::type> {
135 static const bool value = true;
138 template <typename Out, typename Enable = void>
139 struct MapOutputIndicator {
140 static const bool value = false;
143 template <typename Out>
144 struct MapOutputIndicator<Out,
145 typename exists<typename Out::Value>::type> {
146 static const bool value = true;
149 template <typename In, typename InEnable = void>
150 struct KruskalValueSelector {};
152 template <typename In>
153 struct KruskalValueSelector<In,
154 typename enable_if<SequenceInputIndicator<In>, void>::type>
156 typedef typename In::value_type::second_type Value;
159 template <typename In>
160 struct KruskalValueSelector<In,
161 typename enable_if<MapInputIndicator<In>, void>::type>
163 typedef typename In::Value Value;
166 template <typename Graph, typename In, typename Out,
167 typename InEnable = void>
168 struct KruskalInputSelector {};
170 template <typename Graph, typename In, typename Out,
171 typename InEnable = void>
172 struct KruskalOutputSelector {};
174 template <typename Graph, typename In, typename Out>
175 struct KruskalInputSelector<Graph, In, Out,
176 typename enable_if<SequenceInputIndicator<In>, void>::type >
178 typedef typename In::value_type::second_type Value;
180 static Value kruskal(const Graph& graph, const In& in, Out& out) {
181 return KruskalOutputSelector<Graph, In, Out>::
182 kruskal(graph, in, out);
187 template <typename Graph, typename In, typename Out>
188 struct KruskalInputSelector<Graph, In, Out,
189 typename enable_if<MapInputIndicator<In>, void>::type >
191 typedef typename In::Value Value;
192 static Value kruskal(const Graph& graph, const In& in, Out& out) {
193 typedef typename In::Key MapArc;
194 typedef typename In::Value Value;
195 typedef typename ItemSetTraits<Graph, MapArc>::ItemIt MapArcIt;
196 typedef std::vector<std::pair<MapArc, Value> > Sequence;
199 for (MapArcIt it(graph); it != INVALID; ++it) {
200 seq.push_back(std::make_pair(it, in[it]));
203 std::sort(seq.begin(), seq.end(), PairComp<Sequence>());
204 return KruskalOutputSelector<Graph, Sequence, Out>::
205 kruskal(graph, seq, out);
209 template <typename T>
214 template <typename T>
215 struct RemoveConst<const T> {
219 template <typename Graph, typename In, typename Out>
220 struct KruskalOutputSelector<Graph, In, Out,
221 typename enable_if<SequenceOutputIndicator<Out>, void>::type >
223 typedef typename In::value_type::second_type Value;
225 static Value kruskal(const Graph& graph, const In& in, Out& out) {
226 typedef LoggerBoolMap<typename RemoveConst<Out>::type> Map;
228 return _kruskal_bits::kruskal(graph, in, map);
233 template <typename Graph, typename In, typename Out>
234 struct KruskalOutputSelector<Graph, In, Out,
235 typename enable_if<MapOutputIndicator<Out>, void>::type >
237 typedef typename In::value_type::second_type Value;
239 static Value kruskal(const Graph& graph, const In& in, Out& out) {
240 return _kruskal_bits::kruskal(graph, in, out);
246 /// \ingroup spantree
248 /// \brief Kruskal's algorithm for finding a minimum cost spanning tree of
251 /// This function runs Kruskal's algorithm to find a minimum cost
252 /// spanning tree of a graph.
253 /// Due to some C++ hacking, it accepts various input and output types.
255 /// \param g The graph the algorithm runs on.
256 /// It can be either \ref concepts::Digraph "directed" or
257 /// \ref concepts::Graph "undirected".
258 /// If the graph is directed, the algorithm consider it to be
259 /// undirected by disregarding the direction of the arcs.
261 /// \param in This object is used to describe the arc/edge costs.
262 /// It can be one of the following choices.
263 /// - An STL compatible 'Forward Container' with
264 /// <tt>std::pair<GR::Arc,C></tt> or
265 /// <tt>std::pair<GR::Edge,C></tt> as its <tt>value_type</tt>, where
266 /// \c C is the type of the costs. The pairs indicates the arcs/edges
267 /// along with the assigned cost. <em>They must be in a
268 /// cost-ascending order.</em>
269 /// - Any readable arc/edge map. The values of the map indicate the
272 /// \retval out Here we also have a choice.
273 /// - It can be a writable arc/edge map with \c bool value type. After
274 /// running the algorithm it will contain the found minimum cost spanning
275 /// tree: the value of an arc/edge will be set to \c true if it belongs
276 /// to the tree, otherwise it will be set to \c false. The value of
277 /// each arc/edge will be set exactly once.
278 /// - It can also be an iteraror of an STL Container with
279 /// <tt>GR::Arc</tt> or <tt>GR::Edge</tt> as its
280 /// <tt>value_type</tt>. The algorithm copies the elements of the
281 /// found tree into this sequence. For example, if we know that the
282 /// spanning tree of the graph \c g has say 53 arcs, then we can
283 /// put its arcs into an STL vector \c tree with a code like this.
285 /// std::vector<Arc> tree(53);
286 /// kruskal(g,cost,tree.begin());
288 /// Or if we don't know in advance the size of the tree, we can
291 /// std::vector<Arc> tree;
292 /// kruskal(g,cost,std::back_inserter(tree));
295 /// \return The total cost of the found spanning tree.
297 /// \note If the input graph is not (weakly) connected, a spanning
298 /// forest is calculated instead of a spanning tree.
301 template <typename Graph, typename In, typename Out>
302 Value kruskal(const Graph& g, const In& in, Out& out)
304 template <class Graph, class In, class Out>
305 inline typename _kruskal_bits::KruskalValueSelector<In>::Value
306 kruskal(const Graph& graph, const In& in, Out& out)
309 return _kruskal_bits::KruskalInputSelector<Graph, In, Out>::
310 kruskal(graph, in, out);
314 template <class Graph, class In, class Out>
315 inline typename _kruskal_bits::KruskalValueSelector<In>::Value
316 kruskal(const Graph& graph, const In& in, const Out& out)
318 return _kruskal_bits::KruskalInputSelector<Graph, In, const Out>::
319 kruskal(graph, in, out);
324 #endif //LEMON_KRUSKAL_H