| 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
| 2 | * |
| 3 | * This file is a part of LEMON, a generic C++ optimization library. |
| 4 | * |
| 5 | * Copyright (C) 2017 |
| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
| 8 | * |
| 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. |
| 12 | * |
| 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 |
| 15 | * purpose. |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | #ifndef LEMON_COMPACT_GRAPH_H |
| 20 | #define LEMON_COMPACT_GRAPH_H |
| 21 | |
| 22 | ///\ingroup graphs |
| 23 | ///\file |
| 24 | ///\brief CompactDigraph class. |
| 25 | |
| 26 | #include <lemon/core.h> |
| 27 | #include <lemon/bits/graph_extender.h> |
| 28 | |
| 29 | #include <algorithm> |
| 30 | |
| 31 | namespace lemon { |
| 32 | |
| 33 | class CompactDigraphBase { |
| 34 | |
| 35 | public: |
| 36 | |
| 37 | CompactDigraphBase() |
| 38 | : built(false), node_num(0), arc_num(0), |
| 39 | node_first_out(NULL), |
| 40 | arc_target(NULL) {} |
| 41 | |
| 42 | ~CompactDigraphBase() { |
| 43 | if (built) { |
| 44 | delete[] node_first_out; |
| 45 | delete[] arc_target; |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | class Node { |
| 50 | friend class CompactDigraphBase; |
| 51 | protected: |
| 52 | int id; |
| 53 | Node(int _id) : id(_id) {} |
| 54 | public: |
| 55 | Node() {} |
| 56 | Node (Invalid) : id(-1) {} |
| 57 | bool operator==(const Node& node) const { return id == node.id; } |
| 58 | bool operator!=(const Node& node) const { return id != node.id; } |
| 59 | bool operator<(const Node& node) const { return id < node.id; } |
| 60 | }; |
| 61 | |
| 62 | class Arc { |
| 63 | friend class CompactDigraphBase; |
| 64 | protected: |
| 65 | int id; |
| 66 | int source; |
| 67 | Arc(int _id, int _source) : id(_id), source(_source) {} |
| 68 | public: |
| 69 | Arc() { } |
| 70 | Arc (Invalid) : id(-1), source(-1) {} |
| 71 | bool operator==(const Arc& arc) const { return id == arc.id; } |
| 72 | bool operator!=(const Arc& arc) const { return id != arc.id; } |
| 73 | bool operator<(const Arc& arc) const { return id < arc.id; } |
| 74 | }; |
| 75 | |
| 76 | Node source(const Arc& e) const { return Node(e.source); } |
| 77 | Node target(const Arc& e) const { return Node(arc_target[e.id]); } |
| 78 | |
| 79 | void first(Node& n) const { n.id = node_num - 1; } |
| 80 | static void next(Node& n) { --n.id; } |
| 81 | |
| 82 | private: |
| 83 | |
| 84 | void nextSource(Arc& e) const { |
| 85 | if (e.id == -1) return; |
| 86 | int last = node_first_out[e.source] - 1; |
| 87 | while (e.id == last) { |
| 88 | --e.source; |
| 89 | last = node_first_out[e.source] - 1; |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | public: |
| 94 | |
| 95 | void first(Arc& e) const { |
| 96 | e.id = arc_num - 1; |
| 97 | e.source = node_num - 1; |
| 98 | nextSource(e); |
| 99 | } |
| 100 | void next(Arc& e) const { |
| 101 | --e.id; |
| 102 | nextSource(e); |
| 103 | } |
| 104 | |
| 105 | void firstOut(Arc& e, const Node& n) const { |
| 106 | e.source = n.id; |
| 107 | e.id = node_first_out[n.id]; |
| 108 | if (e.id == node_first_out[n.id + 1]) e = INVALID; |
| 109 | } |
| 110 | void nextOut(Arc& e) const { |
| 111 | ++e.id; |
| 112 | if (e.id == node_first_out[e.source + 1]) e = INVALID; |
| 113 | } |
| 114 | |
| 115 | void firstIn(Arc& e, const Node& n) const { |
| 116 | first(e); |
| 117 | while(e != INVALID && target(e) != n) { |
| 118 | next(e); |
| 119 | } |
| 120 | } |
| 121 | void nextIn(Arc& e) const { |
| 122 | Node arcTarget = target(e); |
| 123 | do { |
| 124 | next(e); |
| 125 | } while(e != INVALID && target(e) != arcTarget); |
| 126 | } |
| 127 | |
| 128 | static int id(const Node& n) { return n.id; } |
| 129 | static Node nodeFromId(int id) { return Node(id); } |
| 130 | int maxNodeId() const { return node_num - 1; } |
| 131 | |
| 132 | static int id(const Arc& e) { return e.id; } |
| 133 | Arc arcFromId(int id) const { |
| 134 | int *l = std::upper_bound(node_first_out, node_first_out + node_num, id) - 1; |
| 135 | int src = l - node_first_out; |
| 136 | return Arc(id, src); |
| 137 | } |
| 138 | int maxArcId() const { return arc_num - 1; } |
| 139 | |
| 140 | typedef True NodeNumTag; |
| 141 | typedef True ArcNumTag; |
| 142 | |
| 143 | int nodeNum() const { return node_num; } |
| 144 | int arcNum() const { return arc_num; } |
| 145 | |
| 146 | private: |
| 147 | |
| 148 | template <typename Digraph, typename NodeRefMap> |
| 149 | class ArcLess { |
| 150 | public: |
| 151 | typedef typename Digraph::Arc Arc; |
| 152 | |
| 153 | ArcLess(const Digraph &_graph, const NodeRefMap& _nodeRef) |
| 154 | : digraph(_graph), nodeRef(_nodeRef) {} |
| 155 | |
| 156 | bool operator()(const Arc& left, const Arc& right) const { |
| 157 | return nodeRef[digraph.target(left)] < nodeRef[digraph.target(right)]; |
| 158 | } |
| 159 | private: |
| 160 | const Digraph& digraph; |
| 161 | const NodeRefMap& nodeRef; |
| 162 | }; |
| 163 | |
| 164 | public: |
| 165 | |
| 166 | typedef True BuildTag; |
| 167 | |
| 168 | void clear() { |
| 169 | if (built) { |
| 170 | delete[] node_first_out; |
| 171 | delete[] arc_target; |
| 172 | } |
| 173 | built = false; |
| 174 | node_num = 0; |
| 175 | arc_num = 0; |
| 176 | } |
| 177 | |
| 178 | template <typename Digraph, typename NodeRefMap, typename ArcRefMap> |
| 179 | void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) { |
| 180 | typedef typename Digraph::Node GNode; |
| 181 | typedef typename Digraph::Arc GArc; |
| 182 | |
| 183 | built = true; |
| 184 | |
| 185 | node_num = countNodes(digraph); |
| 186 | arc_num = countArcs(digraph); |
| 187 | |
| 188 | node_first_out = new int[node_num + 1]; |
| 189 | |
| 190 | arc_target = new int[arc_num]; |
| 191 | |
| 192 | int node_index = 0; |
| 193 | for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) { |
| 194 | nodeRef[n] = Node(node_index); |
| 195 | ++node_index; |
| 196 | } |
| 197 | |
| 198 | ArcLess<Digraph, NodeRefMap> arcLess(digraph, nodeRef); |
| 199 | |
| 200 | int arc_index = 0; |
| 201 | for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) { |
| 202 | int source = nodeRef[n].id; |
| 203 | std::vector<GArc> arcs; |
| 204 | for (typename Digraph::OutArcIt e(digraph, n); e != INVALID; ++e) { |
| 205 | arcs.push_back(e); |
| 206 | } |
| 207 | if (!arcs.empty()) { |
| 208 | node_first_out[source] = arc_index; |
| 209 | std::sort(arcs.begin(), arcs.end(), arcLess); |
| 210 | for (typename std::vector<GArc>::iterator it = arcs.begin(); |
| 211 | it != arcs.end(); ++it) { |
| 212 | int target = nodeRef[digraph.target(*it)].id; |
| 213 | arcRef[*it] = Arc(arc_index, source); |
| 214 | arc_target[arc_index] = target; |
| 215 | ++arc_index; |
| 216 | } |
| 217 | } else { |
| 218 | node_first_out[source] = arc_index; |
| 219 | } |
| 220 | } |
| 221 | node_first_out[node_num] = arc_num; |
| 222 | } |
| 223 | |
| 224 | template <typename ArcListIterator> |
| 225 | void build(int n, ArcListIterator first, ArcListIterator last) { |
| 226 | built = true; |
| 227 | |
| 228 | node_num = n; |
| 229 | arc_num = static_cast<int>(std::distance(first, last)); |
| 230 | |
| 231 | node_first_out = new int[node_num + 1]; |
| 232 | |
| 233 | arc_target = new int[arc_num]; |
| 234 | |
| 235 | int arc_index = 0; |
| 236 | for (int i = 0; i != node_num; ++i) { |
| 237 | node_first_out[i] = arc_index; |
| 238 | for ( ; first != last && (*first).first == i; ++first) { |
| 239 | int j = (*first).second; |
| 240 | LEMON_ASSERT(j >= 0 && j < node_num, |
| 241 | "Wrong arc list for CompactDigraph::build()"); |
| 242 | arc_target[arc_index] = j; |
| 243 | ++arc_index; |
| 244 | } |
| 245 | } |
| 246 | LEMON_ASSERT(first == last, |
| 247 | "Wrong arc list for CompactDigraph::build()"); |
| 248 | node_first_out[node_num] = arc_num; |
| 249 | } |
| 250 | |
| 251 | protected: |
| 252 | bool built; |
| 253 | int node_num; |
| 254 | int arc_num; |
| 255 | int *node_first_out; |
| 256 | int *arc_target; |
| 257 | }; |
| 258 | |
| 259 | typedef DigraphExtender<CompactDigraphBase> ExtendedCompactDigraphBase; |
| 260 | |
| 261 | |
| 262 | /// \ingroup graphs |
| 263 | /// |
| 264 | /// \brief A static directed graph class. |
| 265 | /// |
| 266 | /// \ref CompactDigraph is a highly efficient digraph implementation |
| 267 | /// similar to \ref StaticDigraph. It is more memory efficient but does |
| 268 | /// not provide efficient iteration over incoming arcs. |
| 269 | /// |
| 270 | /// It stores only one \c int values for each node and one \c int value |
| 271 | /// for each arc. Its \ref InArcIt implementation is inefficient and |
| 272 | /// provided only for compatibility with the \ref concepts::Digraph "Digraph concept". |
| 273 | /// |
| 274 | /// This type fully conforms to the \ref concepts::Digraph "Digraph concept". |
| 275 | /// Most of its member functions and nested classes are documented |
| 276 | /// only in the concept class. |
| 277 | /// |
| 278 | /// \sa concepts::Digraph |
| 279 | class CompactDigraph : public ExtendedCompactDigraphBase { |
| 280 | |
| 281 | private: |
| 282 | /// Graphs are \e not copy constructible. Use DigraphCopy instead. |
| 283 | CompactDigraph(const CompactDigraph &) : ExtendedCompactDigraphBase() {}; |
| 284 | /// \brief Assignment of a graph to another one is \e not allowed. |
| 285 | /// Use DigraphCopy instead. |
| 286 | void operator=(const CompactDigraph&) {} |
| 287 | |
| 288 | public: |
| 289 | |
| 290 | typedef ExtendedCompactDigraphBase Parent; |
| 291 | |
| 292 | public: |
| 293 | |
| 294 | /// \brief Constructor |
| 295 | /// |
| 296 | /// Default constructor. |
| 297 | CompactDigraph() : Parent() {} |
| 298 | |
| 299 | /// \brief The node with the given index. |
| 300 | /// |
| 301 | /// This function returns the node with the given index. |
| 302 | /// \sa index() |
| 303 | static Node node(int ix) { return Parent::nodeFromId(ix); } |
| 304 | |
| 305 | /// \brief The arc with the given index. |
| 306 | /// |
| 307 | /// This function returns the arc with the given index. |
| 308 | /// \sa index() |
| 309 | Arc arc(int ix) { return arcFromId(ix); } |
| 310 | |
| 311 | /// \brief The index of the given node. |
| 312 | /// |
| 313 | /// This function returns the index of the the given node. |
| 314 | /// \sa node() |
| 315 | static int index(Node node) { return Parent::id(node); } |
| 316 | |
| 317 | /// \brief The index of the given arc. |
| 318 | /// |
| 319 | /// This function returns the index of the the given arc. |
| 320 | /// \sa arc() |
| 321 | static int index(Arc arc) { return Parent::id(arc); } |
| 322 | |
| 323 | /// \brief Number of nodes. |
| 324 | /// |
| 325 | /// This function returns the number of nodes. |
| 326 | int nodeNum() const { return node_num; } |
| 327 | |
| 328 | /// \brief Number of arcs. |
| 329 | /// |
| 330 | /// This function returns the number of arcs. |
| 331 | int arcNum() const { return arc_num; } |
| 332 | |
| 333 | /// \brief Build the digraph copying another digraph. |
| 334 | /// |
| 335 | /// This function builds the digraph copying another digraph of any |
| 336 | /// kind. It can be called more than once, but in such case, the whole |
| 337 | /// structure and all maps will be cleared and rebuilt. |
| 338 | /// |
| 339 | /// This method also makes possible to copy a digraph to a CompactDigraph |
| 340 | /// structure using \ref DigraphCopy. |
| 341 | /// |
| 342 | /// \param digraph An existing digraph to be copied. |
| 343 | /// \param nodeRef The node references will be copied into this map. |
| 344 | /// Its key type must be \c Digraph::Node and its value type must be |
| 345 | /// \c CompactDigraph::Node. |
| 346 | /// It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" |
| 347 | /// concept. |
| 348 | /// \param arcRef The arc references will be copied into this map. |
| 349 | /// Its key type must be \c Digraph::Arc and its value type must be |
| 350 | /// \c CompactDigraph::Arc. |
| 351 | /// It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
| 352 | /// |
| 353 | /// \note If you do not need the arc references, then you could use |
| 354 | /// \ref NullMap for the last parameter. However the node references |
| 355 | /// are required by the function itself, thus they must be readable |
| 356 | /// from the map. |
| 357 | template <typename Digraph, typename NodeRefMap, typename ArcRefMap> |
| 358 | void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) { |
| 359 | if (built) Parent::clear(); |
| 360 | Parent::build(digraph, nodeRef, arcRef); |
| 361 | } |
| 362 | |
| 363 | /// \brief Build the digraph from an arc list. |
| 364 | /// |
| 365 | /// This function builds the digraph from the given arc list. |
| 366 | /// It can be called more than once, but in such case, the whole |
| 367 | /// structure and all maps will be cleared and rebuilt. |
| 368 | /// |
| 369 | /// The list of the arcs must be given in the range <tt>[begin, end)</tt> |
| 370 | /// specified by STL compatible itartors whose \c value_type must be |
| 371 | /// <tt>std::pair<int,int></tt>. |
| 372 | /// Each arc must be specified by a pair of integer indices |
| 373 | /// from the range <tt>[0..n-1]</tt>. <i>The pairs must be in a |
| 374 | /// non-decreasing order with respect to their first values.</i> |
| 375 | /// If the k-th pair in the list is <tt>(i,j)</tt>, then |
| 376 | /// <tt>arc(k-1)</tt> will connect <tt>node(i)</tt> to <tt>node(j)</tt>. |
| 377 | /// |
| 378 | /// \param n The number of nodes. |
| 379 | /// \param begin An iterator pointing to the beginning of the arc list. |
| 380 | /// \param end An iterator pointing to the end of the arc list. |
| 381 | /// |
| 382 | /// For example, a simple digraph can be constructed like this. |
| 383 | /// \code |
| 384 | /// std::vector<std::pair<int,int> > arcs; |
| 385 | /// arcs.push_back(std::make_pair(0,1)); |
| 386 | /// arcs.push_back(std::make_pair(0,2)); |
| 387 | /// arcs.push_back(std::make_pair(1,3)); |
| 388 | /// arcs.push_back(std::make_pair(1,2)); |
| 389 | /// arcs.push_back(std::make_pair(3,0)); |
| 390 | /// CompactDigraph gr; |
| 391 | /// gr.build(4, arcs.begin(), arcs.end()); |
| 392 | /// \endcode |
| 393 | template <typename ArcListIterator> |
| 394 | void build(int n, ArcListIterator begin, ArcListIterator end) { |
| 395 | if (built) Parent::clear(); |
| 396 | CompactDigraphBase::build(n, begin, end); |
| 397 | notifier(Node()).build(); |
| 398 | notifier(Arc()).build(); |
| 399 | } |
| 400 | |
| 401 | /// \brief Clear the digraph. |
| 402 | /// |
| 403 | /// This function erases all nodes and arcs from the digraph. |
| 404 | void clear() { |
| 405 | Parent::clear(); |
| 406 | } |
| 407 | |
| 408 | public: |
| 409 | |
| 410 | Node baseNode(const OutArcIt &arc) const { |
| 411 | return Parent::source(static_cast<const Arc&>(arc)); |
| 412 | } |
| 413 | |
| 414 | Node runningNode(const OutArcIt &arc) const { |
| 415 | return Parent::target(static_cast<const Arc&>(arc)); |
| 416 | } |
| 417 | |
| 418 | Node baseNode(const InArcIt &arc) const { |
| 419 | return Parent::target(static_cast<const Arc&>(arc)); |
| 420 | } |
| 421 | |
| 422 | Node runningNode(const InArcIt &arc) const { |
| 423 | return Parent::source(static_cast<const Arc&>(arc)); |
| 424 | } |
| 425 | |
| 426 | }; |
| 427 | |
| 428 | } |
| 429 | |
| 430 | #endif |