diff --git a/lemon/static_graph.h b/lemon/static_graph.h new file mode 100644 --- /dev/null +++ b/lemon/static_graph.h @@ -0,0 +1,476 @@ +/* -*- C++ -*- + * + * This file is a part of LEMON, a generic C++ optimization library + * + * Copyright (C) 2003-2008 + * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport + * (Egervary Research Group on Combinatorial Optimization, EGRES). + * + * Permission to use, modify and distribute this software is granted + * provided that this copyright notice appears in all copies. For + * precise terms see the accompanying LICENSE file. + * + * This software is provided "AS IS" with no warranty of any kind, + * express or implied, and with no claim as to its suitability for any + * purpose. + * + */ + +#ifndef LEMON_STATIC_GRAPH_H +#define LEMON_STATIC_GRAPH_H + +///\ingroup graphs +///\file +///\brief StaticDigraph class. + +#include +#include + +namespace lemon { + + class StaticDigraphBase { + public: + + StaticDigraphBase() + : built(false), node_num(0), arc_num(0), + node_first_out(NULL), node_first_in(NULL), + arc_source(NULL), arc_target(NULL), + arc_next_in(NULL), arc_next_out(NULL) {} + + ~StaticDigraphBase() { + if (built) { + delete[] node_first_out; + delete[] node_first_in; + delete[] arc_source; + delete[] arc_target; + delete[] arc_next_out; + delete[] arc_next_in; + } + } + + class Node { + friend class StaticDigraphBase; + protected: + int id; + Node(int _id) : id(_id) {} + public: + Node() {} + Node (Invalid) : id(-1) {} + bool operator==(const Node& node) const { return id == node.id; } + bool operator!=(const Node& node) const { return id != node.id; } + bool operator<(const Node& node) const { return id < node.id; } + }; + + class Arc { + friend class StaticDigraphBase; + protected: + int id; + Arc(int _id) : id(_id) {} + public: + Arc() { } + Arc (Invalid) : id(-1) {} + bool operator==(const Arc& arc) const { return id == arc.id; } + bool operator!=(const Arc& arc) const { return id != arc.id; } + bool operator<(const Arc& arc) const { return id < arc.id; } + }; + + Node source(const Arc& e) const { return Node(arc_source[e.id]); } + Node target(const Arc& e) const { return Node(arc_target[e.id]); } + + void first(Node& n) const { n.id = node_num - 1; } + static void next(Node& n) { --n.id; } + + void first(Arc& e) const { e.id = arc_num - 1; } + static void next(Arc& e) { --e.id; } + + void firstOut(Arc& e, const Node& n) const { + e.id = node_first_out[n.id] != node_first_out[n.id + 1] ? + node_first_out[n.id] : -1; + } + void nextOut(Arc& e) const { e.id = arc_next_out[e.id]; } + + void firstIn(Arc& e, const Node& n) const { e.id = node_first_in[n.id]; } + void nextIn(Arc& e) const { e.id = arc_next_in[e.id]; } + + static int id(const Node& n) { return n.id; } + static Node nodeFromId(int id) { return Node(id); } + int maxNodeId() const { return node_num - 1; } + + static int id(const Arc& e) { return e.id; } + static Arc arcFromId(int id) { return Arc(id); } + int maxArcId() const { return arc_num - 1; } + + typedef True NodeNumTag; + typedef True ArcNumTag; + + int nodeNum() const { return node_num; } + int arcNum() const { return arc_num; } + + private: + + template + class ArcLess { + public: + typedef typename Digraph::Arc Arc; + + ArcLess(const Digraph &_graph, const NodeRefMap& _nodeRef) + : digraph(_graph), nodeRef(_nodeRef) {} + + bool operator()(const Arc& left, const Arc& right) const { + return nodeRef[digraph.target(left)] < nodeRef[digraph.target(right)]; + } + private: + const Digraph& digraph; + const NodeRefMap& nodeRef; + }; + + public: + + typedef True BuildTag; + + void clear() { + if (built) { + delete[] node_first_out; + delete[] node_first_in; + delete[] arc_source; + delete[] arc_target; + delete[] arc_next_out; + delete[] arc_next_in; + } + built = false; + node_num = 0; + arc_num = 0; + } + + template + void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) { + typedef typename Digraph::Node GNode; + typedef typename Digraph::Arc GArc; + + built = true; + + node_num = countNodes(digraph); + arc_num = countArcs(digraph); + + node_first_out = new int[node_num + 1]; + node_first_in = new int[node_num]; + + arc_source = new int[arc_num]; + arc_target = new int[arc_num]; + arc_next_out = new int[arc_num]; + arc_next_in = new int[arc_num]; + + int node_index = 0; + for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) { + nodeRef[n] = Node(node_index); + node_first_in[node_index] = -1; + ++node_index; + } + + ArcLess arcLess(digraph, nodeRef); + + int arc_index = 0; + for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) { + int source = nodeRef[n].id; + std::vector arcs; + for (typename Digraph::OutArcIt e(digraph, n); e != INVALID; ++e) { + arcs.push_back(e); + } + if (!arcs.empty()) { + node_first_out[source] = arc_index; + std::sort(arcs.begin(), arcs.end(), arcLess); + for (typename std::vector::iterator it = arcs.begin(); + it != arcs.end(); ++it) { + int target = nodeRef[digraph.target(*it)].id; + arcRef[*it] = Arc(arc_index); + arc_source[arc_index] = source; + arc_target[arc_index] = target; + arc_next_in[arc_index] = node_first_in[target]; + node_first_in[target] = arc_index; + arc_next_out[arc_index] = arc_index + 1; + ++arc_index; + } + arc_next_out[arc_index - 1] = -1; + } else { + node_first_out[source] = arc_index; + } + } + node_first_out[node_num] = arc_num; + } + + template + void build(int n, ArcListIterator first, ArcListIterator last) { + built = true; + + node_num = n; + arc_num = std::distance(first, last); + + node_first_out = new int[node_num + 1]; + node_first_in = new int[node_num]; + + arc_source = new int[arc_num]; + arc_target = new int[arc_num]; + arc_next_out = new int[arc_num]; + arc_next_in = new int[arc_num]; + + for (int i = 0; i != node_num; ++i) { + node_first_in[i] = -1; + } + + int arc_index = 0; + for (int i = 0; i != node_num; ++i) { + node_first_out[i] = arc_index; + for ( ; first != last && (*first).first == i; ++first) { + int j = (*first).second; + LEMON_ASSERT(j >= 0 && j < node_num, + "Wrong arc list for StaticDigraph::build()"); + arc_source[arc_index] = i; + arc_target[arc_index] = j; + arc_next_in[arc_index] = node_first_in[j]; + node_first_in[j] = arc_index; + arc_next_out[arc_index] = arc_index + 1; + ++arc_index; + } + if (arc_index > node_first_out[i]) + arc_next_out[arc_index - 1] = -1; + } + LEMON_ASSERT(first == last, + "Wrong arc list for StaticDigraph::build()"); + node_first_out[node_num] = arc_num; + } + + protected: + + void fastFirstOut(Arc& e, const Node& n) const { + e.id = node_first_out[n.id]; + } + + static void fastNextOut(Arc& e) { + ++e.id; + } + void fastLastOut(Arc& e, const Node& n) const { + e.id = node_first_out[n.id + 1]; + } + + protected: + bool built; + int node_num; + int arc_num; + int *node_first_out; + int *node_first_in; + int *arc_source; + int *arc_target; + int *arc_next_in; + int *arc_next_out; + }; + + typedef DigraphExtender ExtendedStaticDigraphBase; + + + /// \ingroup graphs + /// + /// \brief A static directed graph class. + /// + /// \ref StaticDigraph is a highly efficient digraph implementation, + /// but it is fully static. + /// It stores only two \c int values for each node and only four \c int + /// values for each arc. Moreover it provides faster item iteration than + /// \ref ListDigraph and \ref SmartDigraph, especially using \c OutArcIt + /// iterators, since its arcs are stored in an appropriate order. + /// However it only provides build() and clear() functions and does not + /// support any other modification of the digraph. + /// + /// Since this digraph structure is completely static, its nodes and arcs + /// can be indexed with integers from the ranges [0..nodeNum()-1] + /// and [0..arcNum()-1], respectively. + /// The index of an item is the same as its ID, it can be obtained + /// using the corresponding \ref index() or \ref concepts::Digraph::id() + /// "id()" function. A node or arc with a certain index can be obtained + /// using node() or arc(). + /// + /// This type fully conforms to the \ref concepts::Digraph "Digraph concept". + /// Most of its member functions and nested classes are documented + /// only in the concept class. + /// + /// This class provides constant time counting for nodes and arcs. + /// + /// \sa concepts::Digraph + class StaticDigraph : public ExtendedStaticDigraphBase { + public: + + typedef ExtendedStaticDigraphBase Parent; + + public: + + /// \brief Constructor + /// + /// Default constructor. + StaticDigraph() : Parent() {} + + /// \brief The node with the given index. + /// + /// This function returns the node with the given index. + /// \sa index() + static Node node(int ix) { return Parent::nodeFromId(ix); } + + /// \brief The arc with the given index. + /// + /// This function returns the arc with the given index. + /// \sa index() + static Arc arc(int ix) { return Parent::arcFromId(ix); } + + /// \brief The index of the given node. + /// + /// This function returns the index of the the given node. + /// \sa node() + static int index(Node node) { return Parent::id(node); } + + /// \brief The index of the given arc. + /// + /// This function returns the index of the the given arc. + /// \sa arc() + static int index(Arc arc) { return Parent::id(arc); } + + /// \brief Number of nodes. + /// + /// This function returns the number of nodes. + int nodeNum() const { return node_num; } + + /// \brief Number of arcs. + /// + /// This function returns the number of arcs. + int arcNum() const { return arc_num; } + + /// \brief Build the digraph copying another digraph. + /// + /// This function builds the digraph copying another digraph of any + /// kind. It can be called more than once, but in such case, the whole + /// structure and all maps will be cleared and rebuilt. + /// + /// This method also makes possible to copy a digraph to a StaticDigraph + /// structure using \ref DigraphCopy. + /// + /// \param digraph An existing digraph to be copied. + /// \param nodeRef The node references will be copied into this map. + /// Its key type must be \c Digraph::Node and its value type must be + /// \c StaticDigraph::Node. + /// It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" + /// concept. + /// \param arcRef The arc references will be copied into this map. + /// Its key type must be \c Digraph::Arc and its value type must be + /// \c StaticDigraph::Arc. + /// It must conform to the \ref concepts::WriteMap "WriteMap" concept. + /// + /// \note If you do not need the arc references, then you could use + /// \ref NullMap for the last parameter. However the node references + /// are required by the function itself, thus they must be readable + /// from the map. + template + void build(const Digraph& digraph, NodeRefMap& nodeRef, ArcRefMap& arcRef) { + if (built) Parent::clear(); + Parent::build(digraph, nodeRef, arcRef); + } + + /// \brief Build the digraph from an arc list. + /// + /// This function builds the digraph from the given arc list. + /// It can be called more than once, but in such case, the whole + /// structure and all maps will be cleared and rebuilt. + /// + /// The list of the arcs must be given in the range [begin, end) + /// specified by STL compatible itartors whose \c value_type must be + /// std::pair. + /// Each arc must be specified by a pair of integer indices + /// from the range [0..n-1]. The pairs must be in a + /// non-decreasing order with respect to their first values. + /// If the k-th pair in the list is (i,j), then + /// arc(k-1) will connect node(i) to node(j). + /// + /// \param n The number of nodes. + /// \param begin An iterator pointing to the beginning of the arc list. + /// \param end An iterator pointing to the end of the arc list. + /// + /// For example, a simple digraph can be constructed like this. + /// \code + /// std::vector > arcs; + /// arcs.push_back(std::make_pair(0,1)); + /// arcs.push_back(std::make_pair(0,2)); + /// arcs.push_back(std::make_pair(1,3)); + /// arcs.push_back(std::make_pair(1,2)); + /// arcs.push_back(std::make_pair(3,0)); + /// StaticDigraph gr; + /// gr.build(4, arcs.begin(), arcs.end()); + /// \endcode + template + void build(int n, ArcListIterator begin, ArcListIterator end) { + if (built) Parent::clear(); + StaticDigraphBase::build(n, begin, end); + notifier(Node()).build(); + notifier(Arc()).build(); + } + + /// \brief Clear the digraph. + /// + /// This function erases all nodes and arcs from the digraph. + void clear() { + Parent::clear(); + } + + protected: + + using Parent::fastFirstOut; + using Parent::fastNextOut; + using Parent::fastLastOut; + + public: + + class OutArcIt : public Arc { + public: + + OutArcIt() { } + + OutArcIt(Invalid i) : Arc(i) { } + + OutArcIt(const StaticDigraph& digraph, const Node& node) { + digraph.fastFirstOut(*this, node); + digraph.fastLastOut(last, node); + if (last == *this) *this = INVALID; + } + + OutArcIt(const StaticDigraph& digraph, const Arc& arc) : Arc(arc) { + if (arc != INVALID) { + digraph.fastLastOut(last, digraph.source(arc)); + } + } + + OutArcIt& operator++() { + StaticDigraph::fastNextOut(*this); + if (last == *this) *this = INVALID; + return *this; + } + + private: + Arc last; + }; + + Node baseNode(const OutArcIt &arc) const { + return Parent::source(static_cast(arc)); + } + + Node runningNode(const OutArcIt &arc) const { + return Parent::target(static_cast(arc)); + } + + Node baseNode(const InArcIt &arc) const { + return Parent::target(static_cast(arc)); + } + + Node runningNode(const InArcIt &arc) const { + return Parent::source(static_cast(arc)); + } + + }; + +} + +#endif