alpar@209: /* -*- mode: C++; indent-tabs-mode: nil; -*-
deba@109:  *
alpar@209:  * This file is a part of LEMON, a generic C++ optimization library.
deba@109:  *
alpar@440:  * Copyright (C) 2003-2009
deba@109:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@109:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@109:  *
deba@109:  * Permission to use, modify and distribute this software is granted
deba@109:  * provided that this copyright notice appears in all copies. For
deba@109:  * precise terms see the accompanying LICENSE file.
deba@109:  *
deba@109:  * This software is provided "AS IS" with no warranty of any kind,
deba@109:  * express or implied, and with no claim as to its suitability for any
deba@109:  * purpose.
deba@109:  *
deba@109:  */
deba@109: 
deba@109: #ifndef LEMON_SMART_GRAPH_H
deba@109: #define LEMON_SMART_GRAPH_H
deba@109: 
deba@109: ///\ingroup graphs
deba@109: ///\file
deba@109: ///\brief SmartDigraph and SmartGraph classes.
deba@109: 
deba@109: #include <vector>
deba@109: 
deba@220: #include <lemon/core.h>
deba@109: #include <lemon/error.h>
deba@109: #include <lemon/bits/graph_extender.h>
deba@109: 
deba@109: namespace lemon {
deba@109: 
deba@109:   class SmartDigraph;
deba@109: 
deba@109:   class SmartDigraphBase {
deba@109:   protected:
deba@109: 
alpar@209:     struct NodeT
deba@109:     {
alpar@209:       int first_in, first_out;
deba@109:       NodeT() {}
deba@109:     };
alpar@209:     struct ArcT
deba@109:     {
alpar@209:       int target, source, next_in, next_out;
alpar@209:       ArcT() {}
deba@109:     };
deba@109: 
deba@109:     std::vector<NodeT> nodes;
deba@109:     std::vector<ArcT> arcs;
alpar@209: 
deba@109:   public:
deba@109: 
kpeter@617:     typedef SmartDigraphBase Digraph;
deba@109: 
deba@109:     class Node;
deba@109:     class Arc;
deba@109: 
deba@109:   public:
deba@109: 
deba@109:     SmartDigraphBase() : nodes(), arcs() { }
alpar@209:     SmartDigraphBase(const SmartDigraphBase &_g)
deba@109:       : nodes(_g.nodes), arcs(_g.arcs) { }
alpar@209: 
deba@109:     typedef True NodeNumTag;
kpeter@360:     typedef True ArcNumTag;
deba@109: 
deba@109:     int nodeNum() const { return nodes.size(); }
deba@109:     int arcNum() const { return arcs.size(); }
deba@109: 
deba@109:     int maxNodeId() const { return nodes.size()-1; }
deba@109:     int maxArcId() const { return arcs.size()-1; }
deba@109: 
deba@109:     Node addNode() {
alpar@209:       int n = nodes.size();
deba@109:       nodes.push_back(NodeT());
deba@109:       nodes[n].first_in = -1;
deba@109:       nodes[n].first_out = -1;
deba@109:       return Node(n);
deba@109:     }
alpar@209: 
deba@109:     Arc addArc(Node u, Node v) {
alpar@209:       int n = arcs.size();
deba@109:       arcs.push_back(ArcT());
alpar@209:       arcs[n].source = u._id;
deba@109:       arcs[n].target = v._id;
deba@109:       arcs[n].next_out = nodes[u._id].first_out;
deba@109:       arcs[n].next_in = nodes[v._id].first_in;
deba@109:       nodes[u._id].first_out = nodes[v._id].first_in = n;
deba@109: 
deba@109:       return Arc(n);
deba@109:     }
deba@109: 
deba@109:     void clear() {
deba@109:       arcs.clear();
deba@109:       nodes.clear();
deba@109:     }
deba@109: 
deba@109:     Node source(Arc a) const { return Node(arcs[a._id].source); }
deba@109:     Node target(Arc a) const { return Node(arcs[a._id].target); }
deba@109: 
deba@109:     static int id(Node v) { return v._id; }
deba@109:     static int id(Arc a) { return a._id; }
deba@109: 
deba@109:     static Node nodeFromId(int id) { return Node(id);}
deba@109:     static Arc arcFromId(int id) { return Arc(id);}
deba@109: 
alpar@209:     bool valid(Node n) const {
alpar@209:       return n._id >= 0 && n._id < static_cast<int>(nodes.size());
deba@149:     }
alpar@209:     bool valid(Arc a) const {
alpar@209:       return a._id >= 0 && a._id < static_cast<int>(arcs.size());
deba@149:     }
deba@149: 
deba@109:     class Node {
deba@109:       friend class SmartDigraphBase;
deba@109:       friend class SmartDigraph;
deba@109: 
deba@109:     protected:
deba@109:       int _id;
deba@109:       explicit Node(int id) : _id(id) {}
deba@109:     public:
deba@109:       Node() {}
deba@109:       Node (Invalid) : _id(-1) {}
deba@109:       bool operator==(const Node i) const {return _id == i._id;}
deba@109:       bool operator!=(const Node i) const {return _id != i._id;}
deba@109:       bool operator<(const Node i) const {return _id < i._id;}
deba@109:     };
alpar@209: 
deba@109: 
deba@109:     class Arc {
deba@109:       friend class SmartDigraphBase;
deba@109:       friend class SmartDigraph;
deba@109: 
deba@109:     protected:
deba@109:       int _id;
deba@109:       explicit Arc(int id) : _id(id) {}
deba@109:     public:
deba@109:       Arc() { }
deba@109:       Arc (Invalid) : _id(-1) {}
deba@109:       bool operator==(const Arc i) const {return _id == i._id;}
deba@109:       bool operator!=(const Arc i) const {return _id != i._id;}
deba@109:       bool operator<(const Arc i) const {return _id < i._id;}
deba@109:     };
deba@109: 
deba@109:     void first(Node& node) const {
deba@109:       node._id = nodes.size() - 1;
deba@109:     }
deba@109: 
deba@109:     static void next(Node& node) {
deba@109:       --node._id;
deba@109:     }
deba@109: 
deba@109:     void first(Arc& arc) const {
deba@109:       arc._id = arcs.size() - 1;
deba@109:     }
deba@109: 
deba@109:     static void next(Arc& arc) {
deba@109:       --arc._id;
deba@109:     }
deba@109: 
deba@109:     void firstOut(Arc& arc, const Node& node) const {
deba@109:       arc._id = nodes[node._id].first_out;
deba@109:     }
deba@109: 
deba@109:     void nextOut(Arc& arc) const {
deba@109:       arc._id = arcs[arc._id].next_out;
deba@109:     }
deba@109: 
deba@109:     void firstIn(Arc& arc, const Node& node) const {
deba@109:       arc._id = nodes[node._id].first_in;
deba@109:     }
alpar@209: 
deba@109:     void nextIn(Arc& arc) const {
deba@109:       arc._id = arcs[arc._id].next_in;
deba@109:     }
deba@109: 
deba@109:   };
deba@109: 
deba@109:   typedef DigraphExtender<SmartDigraphBase> ExtendedSmartDigraphBase;
deba@109: 
deba@109:   ///\ingroup graphs
deba@109:   ///
deba@109:   ///\brief A smart directed graph class.
deba@109:   ///
kpeter@735:   ///\ref SmartDigraph is a simple and fast digraph implementation.
kpeter@735:   ///It is also quite memory efficient but at the price
kpeter@735:   ///that it does not support node and arc deletion 
kpeter@735:   ///(except for the Snapshot feature).
deba@109:   ///
kpeter@735:   ///This type fully conforms to the \ref concepts::Digraph "Digraph concept"
kpeter@735:   ///and it also provides some additional functionalities.
kpeter@735:   ///Most of its member functions and nested classes are documented
kpeter@735:   ///only in the concept class.
kpeter@735:   ///
kpeter@735:   ///\sa concepts::Digraph
kpeter@735:   ///\sa SmartGraph
deba@109:   class SmartDigraph : public ExtendedSmartDigraphBase {
deba@109:     typedef ExtendedSmartDigraphBase Parent;
deba@109: 
deba@109:   private:
kpeter@735:     /// Digraphs are \e not copy constructible. Use DigraphCopy instead.
deba@109:     SmartDigraph(const SmartDigraph &) : ExtendedSmartDigraphBase() {};
kpeter@735:     /// \brief Assignment of a digraph to another one is \e not allowed.
kpeter@735:     /// Use DigraphCopy instead.
deba@109:     void operator=(const SmartDigraph &) {}
deba@109: 
deba@109:   public:
alpar@209: 
deba@109:     /// Constructor
alpar@209: 
deba@109:     /// Constructor.
deba@109:     ///
deba@109:     SmartDigraph() {};
alpar@209: 
deba@109:     ///Add a new node to the digraph.
alpar@209: 
kpeter@735:     ///This function adds a new node to the digraph.
kpeter@735:     ///\return The new node.
deba@109:     Node addNode() { return Parent::addNode(); }
alpar@209: 
deba@109:     ///Add a new arc to the digraph.
alpar@209: 
kpeter@735:     ///This function adds a new arc to the digraph with source node \c s
deba@109:     ///and target node \c t.
kpeter@559:     ///\return The new arc.
kpeter@735:     Arc addArc(Node s, Node t) {
alpar@209:       return Parent::addArc(s, t);
deba@109:     }
deba@109: 
deba@149:     /// \brief Node validity check
deba@149:     ///
kpeter@735:     /// This function gives back \c true if the given node is valid,
kpeter@735:     /// i.e. it is a real node of the digraph.
deba@149:     ///
deba@149:     /// \warning A removed node (using Snapshot) could become valid again
kpeter@735:     /// if new nodes are added to the digraph.
deba@149:     bool valid(Node n) const { return Parent::valid(n); }
deba@149: 
deba@149:     /// \brief Arc validity check
deba@149:     ///
kpeter@735:     /// This function gives back \c true if the given arc is valid,
kpeter@735:     /// i.e. it is a real arc of the digraph.
deba@149:     ///
deba@149:     /// \warning A removed arc (using Snapshot) could become valid again
kpeter@735:     /// if new arcs are added to the graph.
deba@149:     bool valid(Arc a) const { return Parent::valid(a); }
deba@149: 
deba@109:     ///Split a node.
alpar@209: 
kpeter@735:     ///This function splits the given node. First, a new node is added
kpeter@735:     ///to the digraph, then the source of each outgoing arc of node \c n
kpeter@735:     ///is moved to this new node.
kpeter@735:     ///If the second parameter \c connect is \c true (this is the default
kpeter@735:     ///value), then a new arc from node \c n to the newly created node
kpeter@735:     ///is also added.
deba@109:     ///\return The newly created node.
deba@109:     ///
kpeter@735:     ///\note All iterators remain valid.
kpeter@735:     ///
deba@109:     ///\warning This functionality cannot be used together with the Snapshot
deba@109:     ///feature.
deba@109:     Node split(Node n, bool connect = true)
deba@109:     {
deba@109:       Node b = addNode();
deba@109:       nodes[b._id].first_out=nodes[n._id].first_out;
deba@109:       nodes[n._id].first_out=-1;
kpeter@370:       for(int i=nodes[b._id].first_out; i!=-1; i=arcs[i].next_out) {
kpeter@370:         arcs[i].source=b._id;
kpeter@370:       }
deba@109:       if(connect) addArc(n,b);
deba@109:       return b;
deba@109:     }
deba@109: 
kpeter@735:     ///Clear the digraph.
kpeter@735: 
kpeter@735:     ///This function erases all nodes and arcs from the digraph.
kpeter@735:     ///
kpeter@735:     void clear() {
kpeter@735:       Parent::clear();
kpeter@735:     }
kpeter@735: 
kpeter@735:     /// Reserve memory for nodes.
kpeter@735: 
kpeter@735:     /// Using this function, it is possible to avoid superfluous memory
kpeter@735:     /// allocation: if you know that the digraph you want to build will
kpeter@735:     /// be large (e.g. it will contain millions of nodes and/or arcs),
kpeter@735:     /// then it is worth reserving space for this amount before starting
kpeter@735:     /// to build the digraph.
kpeter@735:     /// \sa reserveArc()
kpeter@735:     void reserveNode(int n) { nodes.reserve(n); };
kpeter@735: 
kpeter@735:     /// Reserve memory for arcs.
kpeter@735: 
kpeter@735:     /// Using this function, it is possible to avoid superfluous memory
kpeter@735:     /// allocation: if you know that the digraph you want to build will
kpeter@735:     /// be large (e.g. it will contain millions of nodes and/or arcs),
kpeter@735:     /// then it is worth reserving space for this amount before starting
kpeter@735:     /// to build the digraph.
kpeter@735:     /// \sa reserveNode()
kpeter@735:     void reserveArc(int m) { arcs.reserve(m); };
kpeter@735: 
deba@109:   public:
alpar@209: 
deba@109:     class Snapshot;
deba@109: 
deba@109:   protected:
deba@109: 
deba@109:     void restoreSnapshot(const Snapshot &s)
deba@109:     {
deba@109:       while(s.arc_num<arcs.size()) {
deba@109:         Arc arc = arcFromId(arcs.size()-1);
alpar@209:         Parent::notifier(Arc()).erase(arc);
alpar@209:         nodes[arcs.back().source].first_out=arcs.back().next_out;
alpar@209:         nodes[arcs.back().target].first_in=arcs.back().next_in;
alpar@209:         arcs.pop_back();
deba@109:       }
deba@109:       while(s.node_num<nodes.size()) {
deba@109:         Node node = nodeFromId(nodes.size()-1);
alpar@209:         Parent::notifier(Node()).erase(node);
alpar@209:         nodes.pop_back();
deba@109:       }
alpar@209:     }
deba@109: 
deba@109:   public:
deba@109: 
kpeter@735:     ///Class to make a snapshot of the digraph and to restore it later.
deba@109: 
kpeter@735:     ///Class to make a snapshot of the digraph and to restore it later.
deba@109:     ///
deba@109:     ///The newly added nodes and arcs can be removed using the
kpeter@735:     ///restore() function. This is the only way for deleting nodes and/or
kpeter@735:     ///arcs from a SmartDigraph structure.
deba@109:     ///
kpeter@735:     ///\note After a state is restored, you cannot restore a later state, 
kpeter@735:     ///i.e. you cannot add the removed nodes and arcs again using
kpeter@735:     ///another Snapshot instance.
kpeter@735:     ///
kpeter@735:     ///\warning Node splitting cannot be restored.
kpeter@735:     ///\warning The validity of the snapshot is not stored due to
kpeter@735:     ///performance reasons. If you do not use the snapshot correctly,
kpeter@735:     ///it can cause broken program, invalid or not restored state of
kpeter@735:     ///the digraph or no change.
alpar@209:     class Snapshot
deba@109:     {
deba@109:       SmartDigraph *_graph;
deba@109:     protected:
deba@109:       friend class SmartDigraph;
deba@109:       unsigned int node_num;
deba@109:       unsigned int arc_num;
deba@109:     public:
deba@109:       ///Default constructor.
alpar@209: 
deba@109:       ///Default constructor.
kpeter@735:       ///You have to call save() to actually make a snapshot.
deba@109:       Snapshot() : _graph(0) {}
deba@109:       ///Constructor that immediately makes a snapshot
alpar@209: 
kpeter@735:       ///This constructor immediately makes a snapshot of the given digraph.
kpeter@735:       ///
kpeter@735:       Snapshot(SmartDigraph &gr) : _graph(&gr) {
alpar@209:         node_num=_graph->nodes.size();
alpar@209:         arc_num=_graph->arcs.size();
deba@109:       }
deba@109: 
deba@109:       ///Make a snapshot.
deba@109: 
kpeter@735:       ///This function makes a snapshot of the given digraph.
kpeter@735:       ///It can be called more than once. In case of a repeated
deba@109:       ///call, the previous snapshot gets lost.
kpeter@735:       void save(SmartDigraph &gr) {
kpeter@735:         _graph=&gr;
alpar@209:         node_num=_graph->nodes.size();
alpar@209:         arc_num=_graph->arcs.size();
deba@109:       }
deba@109: 
deba@109:       ///Undo the changes until a snapshot.
alpar@209: 
kpeter@735:       ///This function undos the changes until the last snapshot
kpeter@735:       ///created by save() or Snapshot(SmartDigraph&).
deba@109:       void restore()
deba@109:       {
alpar@209:         _graph->restoreSnapshot(*this);
deba@109:       }
deba@109:     };
deba@109:   };
deba@109: 
deba@109: 
deba@109:   class SmartGraphBase {
deba@109: 
deba@109:   protected:
deba@109: 
deba@109:     struct NodeT {
deba@109:       int first_out;
deba@109:     };
alpar@209: 
deba@109:     struct ArcT {
deba@109:       int target;
deba@109:       int next_out;
deba@109:     };
deba@109: 
deba@109:     std::vector<NodeT> nodes;
deba@109:     std::vector<ArcT> arcs;
deba@109: 
deba@109:     int first_free_arc;
alpar@209: 
deba@109:   public:
alpar@209: 
kpeter@617:     typedef SmartGraphBase Graph;
deba@109: 
deba@109:     class Node;
deba@109:     class Arc;
deba@109:     class Edge;
alpar@209: 
deba@109:     class Node {
deba@109:       friend class SmartGraphBase;
deba@109:     protected:
deba@109: 
deba@109:       int _id;
deba@109:       explicit Node(int id) { _id = id;}
deba@109: 
deba@109:     public:
deba@109:       Node() {}
deba@109:       Node (Invalid) { _id = -1; }
deba@109:       bool operator==(const Node& node) const {return _id == node._id;}
deba@109:       bool operator!=(const Node& node) const {return _id != node._id;}
deba@109:       bool operator<(const Node& node) const {return _id < node._id;}
deba@109:     };
deba@109: 
deba@109:     class Edge {
deba@109:       friend class SmartGraphBase;
deba@109:     protected:
deba@109: 
deba@109:       int _id;
deba@109:       explicit Edge(int id) { _id = id;}
deba@109: 
deba@109:     public:
deba@109:       Edge() {}
deba@109:       Edge (Invalid) { _id = -1; }
deba@109:       bool operator==(const Edge& arc) const {return _id == arc._id;}
deba@109:       bool operator!=(const Edge& arc) const {return _id != arc._id;}
deba@109:       bool operator<(const Edge& arc) const {return _id < arc._id;}
deba@109:     };
deba@109: 
deba@109:     class Arc {
deba@109:       friend class SmartGraphBase;
deba@109:     protected:
deba@109: 
deba@109:       int _id;
deba@109:       explicit Arc(int id) { _id = id;}
deba@109: 
deba@109:     public:
kpeter@329:       operator Edge() const {
kpeter@329:         return _id != -1 ? edgeFromId(_id / 2) : INVALID;
deba@238:       }
deba@109: 
deba@109:       Arc() {}
deba@109:       Arc (Invalid) { _id = -1; }
deba@109:       bool operator==(const Arc& arc) const {return _id == arc._id;}
deba@109:       bool operator!=(const Arc& arc) const {return _id != arc._id;}
deba@109:       bool operator<(const Arc& arc) const {return _id < arc._id;}
deba@109:     };
deba@109: 
deba@109: 
deba@109: 
deba@109:     SmartGraphBase()
deba@109:       : nodes(), arcs() {}
deba@109: 
kpeter@368:     typedef True NodeNumTag;
kpeter@368:     typedef True EdgeNumTag;
kpeter@368:     typedef True ArcNumTag;
kpeter@368: 
kpeter@368:     int nodeNum() const { return nodes.size(); }
kpeter@368:     int edgeNum() const { return arcs.size() / 2; }
kpeter@368:     int arcNum() const { return arcs.size(); }
alpar@209: 
alpar@209:     int maxNodeId() const { return nodes.size()-1; }
deba@109:     int maxEdgeId() const { return arcs.size() / 2 - 1; }
deba@109:     int maxArcId() const { return arcs.size()-1; }
deba@109: 
deba@109:     Node source(Arc e) const { return Node(arcs[e._id ^ 1].target); }
deba@109:     Node target(Arc e) const { return Node(arcs[e._id].target); }
deba@109: 
deba@125:     Node u(Edge e) const { return Node(arcs[2 * e._id].target); }
deba@125:     Node v(Edge e) const { return Node(arcs[2 * e._id + 1].target); }
deba@109: 
deba@109:     static bool direction(Arc e) {
deba@109:       return (e._id & 1) == 1;
deba@109:     }
deba@109: 
deba@109:     static Arc direct(Edge e, bool d) {
deba@109:       return Arc(e._id * 2 + (d ? 1 : 0));
deba@109:     }
deba@109: 
alpar@209:     void first(Node& node) const {
deba@109:       node._id = nodes.size() - 1;
deba@109:     }
deba@109: 
kpeter@778:     static void next(Node& node) {
deba@109:       --node._id;
deba@109:     }
deba@109: 
alpar@209:     void first(Arc& arc) const {
deba@109:       arc._id = arcs.size() - 1;
deba@109:     }
deba@109: 
kpeter@778:     static void next(Arc& arc) {
deba@109:       --arc._id;
deba@109:     }
deba@109: 
alpar@209:     void first(Edge& arc) const {
deba@109:       arc._id = arcs.size() / 2 - 1;
deba@109:     }
deba@109: 
kpeter@778:     static void next(Edge& arc) {
deba@109:       --arc._id;
deba@109:     }
deba@109: 
deba@109:     void firstOut(Arc &arc, const Node& v) const {
deba@109:       arc._id = nodes[v._id].first_out;
deba@109:     }
deba@109:     void nextOut(Arc &arc) const {
deba@109:       arc._id = arcs[arc._id].next_out;
deba@109:     }
deba@109: 
deba@109:     void firstIn(Arc &arc, const Node& v) const {
deba@109:       arc._id = ((nodes[v._id].first_out) ^ 1);
deba@109:       if (arc._id == -2) arc._id = -1;
deba@109:     }
deba@109:     void nextIn(Arc &arc) const {
deba@109:       arc._id = ((arcs[arc._id ^ 1].next_out) ^ 1);
deba@109:       if (arc._id == -2) arc._id = -1;
deba@109:     }
deba@109: 
deba@109:     void firstInc(Edge &arc, bool& d, const Node& v) const {
deba@109:       int de = nodes[v._id].first_out;
deba@109:       if (de != -1) {
deba@109:         arc._id = de / 2;
deba@109:         d = ((de & 1) == 1);
deba@109:       } else {
deba@109:         arc._id = -1;
deba@109:         d = true;
deba@109:       }
deba@109:     }
deba@109:     void nextInc(Edge &arc, bool& d) const {
deba@109:       int de = (arcs[(arc._id * 2) | (d ? 1 : 0)].next_out);
deba@109:       if (de != -1) {
deba@109:         arc._id = de / 2;
deba@109:         d = ((de & 1) == 1);
deba@109:       } else {
deba@109:         arc._id = -1;
alpar@209:         d = true;
deba@109:       }
deba@109:     }
alpar@209: 
deba@109:     static int id(Node v) { return v._id; }
deba@109:     static int id(Arc e) { return e._id; }
deba@109:     static int id(Edge e) { return e._id; }
deba@109: 
deba@109:     static Node nodeFromId(int id) { return Node(id);}
deba@109:     static Arc arcFromId(int id) { return Arc(id);}
deba@109:     static Edge edgeFromId(int id) { return Edge(id);}
deba@109: 
alpar@209:     bool valid(Node n) const {
alpar@209:       return n._id >= 0 && n._id < static_cast<int>(nodes.size());
deba@149:     }
alpar@209:     bool valid(Arc a) const {
deba@149:       return a._id >= 0 && a._id < static_cast<int>(arcs.size());
deba@149:     }
alpar@209:     bool valid(Edge e) const {
alpar@209:       return e._id >= 0 && 2 * e._id < static_cast<int>(arcs.size());
deba@149:     }
deba@149: 
alpar@209:     Node addNode() {
deba@109:       int n = nodes.size();
deba@109:       nodes.push_back(NodeT());
deba@109:       nodes[n].first_out = -1;
alpar@209: 
deba@109:       return Node(n);
deba@109:     }
alpar@209: 
deba@138:     Edge addEdge(Node u, Node v) {
deba@109:       int n = arcs.size();
deba@109:       arcs.push_back(ArcT());
deba@109:       arcs.push_back(ArcT());
alpar@209: 
deba@109:       arcs[n].target = u._id;
deba@109:       arcs[n | 1].target = v._id;
deba@109: 
deba@109:       arcs[n].next_out = nodes[v._id].first_out;
deba@109:       nodes[v._id].first_out = n;
deba@109: 
alpar@209:       arcs[n | 1].next_out = nodes[u._id].first_out;
deba@109:       nodes[u._id].first_out = (n | 1);
deba@109: 
deba@109:       return Edge(n / 2);
deba@109:     }
alpar@209: 
deba@109:     void clear() {
deba@109:       arcs.clear();
deba@109:       nodes.clear();
deba@109:     }
deba@109: 
deba@109:   };
deba@109: 
deba@109:   typedef GraphExtender<SmartGraphBase> ExtendedSmartGraphBase;
deba@109: 
deba@109:   /// \ingroup graphs
deba@109:   ///
deba@109:   /// \brief A smart undirected graph class.
deba@109:   ///
kpeter@735:   /// \ref SmartGraph is a simple and fast graph implementation.
kpeter@735:   /// It is also quite memory efficient but at the price
kpeter@735:   /// that it does not support node and edge deletion 
kpeter@735:   /// (except for the Snapshot feature).
deba@109:   ///
kpeter@735:   /// This type fully conforms to the \ref concepts::Graph "Graph concept"
kpeter@735:   /// and it also provides some additional functionalities.
kpeter@735:   /// Most of its member functions and nested classes are documented
kpeter@735:   /// only in the concept class.
kpeter@735:   ///
kpeter@735:   /// \sa concepts::Graph
kpeter@735:   /// \sa SmartDigraph
deba@109:   class SmartGraph : public ExtendedSmartGraphBase {
kpeter@617:     typedef ExtendedSmartGraphBase Parent;
kpeter@617: 
deba@109:   private:
kpeter@735:     /// Graphs are \e not copy constructible. Use GraphCopy instead.
deba@109:     SmartGraph(const SmartGraph &) : ExtendedSmartGraphBase() {};
kpeter@735:     /// \brief Assignment of a graph to another one is \e not allowed.
kpeter@735:     /// Use GraphCopy instead.
deba@109:     void operator=(const SmartGraph &) {}
deba@109: 
deba@109:   public:
deba@109: 
deba@109:     /// Constructor
alpar@209: 
deba@109:     /// Constructor.
deba@109:     ///
deba@109:     SmartGraph() {}
deba@109: 
kpeter@735:     /// \brief Add a new node to the graph.
kpeter@735:     ///
kpeter@735:     /// This function adds a new node to the graph.
kpeter@559:     /// \return The new node.
deba@109:     Node addNode() { return Parent::addNode(); }
alpar@209: 
kpeter@735:     /// \brief Add a new edge to the graph.
kpeter@735:     ///
kpeter@735:     /// This function adds a new edge to the graph between nodes
kpeter@735:     /// \c u and \c v with inherent orientation from node \c u to
kpeter@735:     /// node \c v.
kpeter@735:     /// \return The new edge.
kpeter@735:     Edge addEdge(Node u, Node v) {
kpeter@735:       return Parent::addEdge(u, v);
deba@109:     }
deba@109: 
deba@149:     /// \brief Node validity check
deba@149:     ///
kpeter@735:     /// This function gives back \c true if the given node is valid,
kpeter@735:     /// i.e. it is a real node of the graph.
deba@149:     ///
deba@149:     /// \warning A removed node (using Snapshot) could become valid again
kpeter@735:     /// if new nodes are added to the graph.
deba@149:     bool valid(Node n) const { return Parent::valid(n); }
deba@149: 
kpeter@735:     /// \brief Edge validity check
kpeter@735:     ///
kpeter@735:     /// This function gives back \c true if the given edge is valid,
kpeter@735:     /// i.e. it is a real edge of the graph.
kpeter@735:     ///
kpeter@735:     /// \warning A removed edge (using Snapshot) could become valid again
kpeter@735:     /// if new edges are added to the graph.
kpeter@735:     bool valid(Edge e) const { return Parent::valid(e); }
kpeter@735: 
deba@149:     /// \brief Arc validity check
deba@149:     ///
kpeter@735:     /// This function gives back \c true if the given arc is valid,
kpeter@735:     /// i.e. it is a real arc of the graph.
deba@149:     ///
deba@149:     /// \warning A removed arc (using Snapshot) could become valid again
kpeter@735:     /// if new edges are added to the graph.
deba@149:     bool valid(Arc a) const { return Parent::valid(a); }
deba@149: 
deba@109:     ///Clear the graph.
alpar@209: 
kpeter@735:     ///This function erases all nodes and arcs from the graph.
deba@109:     ///
deba@109:     void clear() {
deba@109:       Parent::clear();
deba@109:     }
deba@109: 
kpeter@736:     /// Reserve memory for nodes.
kpeter@736: 
kpeter@736:     /// Using this function, it is possible to avoid superfluous memory
kpeter@736:     /// allocation: if you know that the graph you want to build will
kpeter@736:     /// be large (e.g. it will contain millions of nodes and/or edges),
kpeter@736:     /// then it is worth reserving space for this amount before starting
kpeter@736:     /// to build the graph.
kpeter@736:     /// \sa reserveEdge()
kpeter@736:     void reserveNode(int n) { nodes.reserve(n); };
kpeter@736: 
kpeter@736:     /// Reserve memory for edges.
kpeter@736: 
kpeter@736:     /// Using this function, it is possible to avoid superfluous memory
kpeter@736:     /// allocation: if you know that the graph you want to build will
kpeter@736:     /// be large (e.g. it will contain millions of nodes and/or edges),
kpeter@736:     /// then it is worth reserving space for this amount before starting
kpeter@736:     /// to build the graph.
kpeter@736:     /// \sa reserveNode()
kpeter@736:     void reserveEdge(int m) { arcs.reserve(2 * m); };
kpeter@736: 
deba@109:   public:
alpar@209: 
deba@109:     class Snapshot;
deba@109: 
deba@109:   protected:
deba@109: 
deba@109:     void saveSnapshot(Snapshot &s)
deba@109:     {
deba@109:       s._graph = this;
deba@109:       s.node_num = nodes.size();
deba@109:       s.arc_num = arcs.size();
deba@109:     }
deba@109: 
deba@109:     void restoreSnapshot(const Snapshot &s)
deba@109:     {
deba@109:       while(s.arc_num<arcs.size()) {
deba@109:         int n=arcs.size()-1;
deba@109:         Edge arc=edgeFromId(n/2);
alpar@209:         Parent::notifier(Edge()).erase(arc);
deba@109:         std::vector<Arc> dir;
deba@109:         dir.push_back(arcFromId(n));
deba@109:         dir.push_back(arcFromId(n-1));
alpar@209:         Parent::notifier(Arc()).erase(dir);
kpeter@373:         nodes[arcs[n-1].target].first_out=arcs[n].next_out;
kpeter@373:         nodes[arcs[n].target].first_out=arcs[n-1].next_out;
alpar@209:         arcs.pop_back();
alpar@209:         arcs.pop_back();
deba@109:       }
deba@109:       while(s.node_num<nodes.size()) {
deba@109:         int n=nodes.size()-1;
deba@109:         Node node = nodeFromId(n);
alpar@209:         Parent::notifier(Node()).erase(node);
alpar@209:         nodes.pop_back();
deba@109:       }
alpar@209:     }
deba@109: 
deba@109:   public:
deba@109: 
kpeter@735:     ///Class to make a snapshot of the graph and to restore it later.
deba@109: 
kpeter@735:     ///Class to make a snapshot of the graph and to restore it later.
deba@109:     ///
kpeter@735:     ///The newly added nodes and edges can be removed using the
kpeter@735:     ///restore() function. This is the only way for deleting nodes and/or
kpeter@735:     ///edges from a SmartGraph structure.
deba@109:     ///
kpeter@735:     ///\note After a state is restored, you cannot restore a later state, 
kpeter@735:     ///i.e. you cannot add the removed nodes and edges again using
kpeter@735:     ///another Snapshot instance.
deba@109:     ///
kpeter@735:     ///\warning The validity of the snapshot is not stored due to
kpeter@735:     ///performance reasons. If you do not use the snapshot correctly,
kpeter@735:     ///it can cause broken program, invalid or not restored state of
kpeter@735:     ///the graph or no change.
alpar@209:     class Snapshot
deba@109:     {
deba@109:       SmartGraph *_graph;
deba@109:     protected:
deba@109:       friend class SmartGraph;
deba@109:       unsigned int node_num;
deba@109:       unsigned int arc_num;
deba@109:     public:
deba@109:       ///Default constructor.
alpar@209: 
deba@109:       ///Default constructor.
kpeter@735:       ///You have to call save() to actually make a snapshot.
deba@109:       Snapshot() : _graph(0) {}
deba@109:       ///Constructor that immediately makes a snapshot
alpar@209: 
kpeter@735:       /// This constructor immediately makes a snapshot of the given graph.
kpeter@735:       ///
kpeter@735:       Snapshot(SmartGraph &gr) {
kpeter@735:         gr.saveSnapshot(*this);
deba@109:       }
deba@109: 
deba@109:       ///Make a snapshot.
deba@109: 
kpeter@735:       ///This function makes a snapshot of the given graph.
kpeter@735:       ///It can be called more than once. In case of a repeated
deba@109:       ///call, the previous snapshot gets lost.
kpeter@735:       void save(SmartGraph &gr)
deba@109:       {
kpeter@735:         gr.saveSnapshot(*this);
deba@109:       }
deba@109: 
kpeter@735:       ///Undo the changes until the last snapshot.
alpar@209: 
kpeter@735:       ///This function undos the changes until the last snapshot
kpeter@735:       ///created by save() or Snapshot(SmartGraph&).
deba@109:       void restore()
deba@109:       {
deba@109:         _graph->restoreSnapshot(*this);
deba@109:       }
deba@109:     };
deba@109:   };
alpar@209: 
deba@109: } //namespace lemon
deba@109: 
deba@109: 
deba@109: #endif //LEMON_SMART_GRAPH_H