COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/hugo/smart_graph.h @ 798:6d1abeb62dd3

Last change on this file since 798:6d1abeb62dd3 was 798:6d1abeb62dd3, checked in by Balazs Dezso, 16 years ago
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Line 
1// -*- mode:C++ -*-
2
3#ifndef HUGO_SMART_GRAPH_H
4#define HUGO_SMART_GRAPH_H
5
6///\ingroup graphs
7///\file
8///\brief SmartGraph and SymSmartGraph classes.
9
10#include <vector>
11#include <climits>
12
13#include <hugo/invalid.h>
14
15#include <hugo/default_map_factory.h>
16#include <hugo/sym_map_factory.h>
17#include <hugo/map_registry.h>
18
19#include <hugo/map_defines.h>
20
21namespace hugo {
22
23/// \addtogroup graphs
24/// @{
25//  class SymSmartGraph;
26
27  ///A smart graph class.
28
29  ///This is a simple and fast graph implementation.
30  ///It is also quite memory efficient, but at the price
31  ///that <b> it does not support node and edge deletion</b>.
32  ///It conforms to the graph interface documented under
33  ///the description of \ref GraphSkeleton.
34  ///\sa \ref GraphSkeleton.
35  ///
36  ///\todo Some member functions could be \c static.
37  ///
38  ///\todo A possibly useful functionality: a function saveState() would
39  ///give back a data sturcture X and then the function restoreState(X)
40  ///would remove the nodes and edges added after the call of saveState().
41  ///Of course it should be used as a stack. (Maybe X is not necessary.)
42  ///
43  ///\author Alpar Juttner
44  class SmartGraph {
45
46    struct NodeT
47    {
48      int first_in,first_out;     
49      NodeT() : first_in(-1), first_out(-1) {}
50    };
51    struct EdgeT
52    {
53      int head, tail, next_in, next_out;     
54      //FIXME: is this necessary?
55      EdgeT() : next_in(-1), next_out(-1) {} 
56    };
57
58    std::vector<NodeT> nodes;
59
60    std::vector<EdgeT> edges;
61   
62   
63  public:
64
65    typedef SmartGraph Graph;
66
67    class Node;
68    class Edge;
69
70    class NodeIt;
71    class EdgeIt;
72    class OutEdgeIt;
73    class InEdgeIt;
74   
75    CREATE_MAP_REGISTRIES;
76    CREATE_MAPS(DefaultMapFactory);
77   
78  public:
79
80    SmartGraph() : nodes(), edges() { }
81    SmartGraph(const SmartGraph &_g) : nodes(_g.nodes), edges(_g.edges) { }
82   
83    int nodeNum() const { return nodes.size(); }  //FIXME: What is this?
84    int edgeNum() const { return edges.size(); }  //FIXME: What is this?
85
86    ///\bug This function does something different than
87    ///its name would suggests...
88    int maxNodeId() const { return nodes.size(); }  //FIXME: What is this?
89    ///\bug This function does something different than
90    ///its name would suggests...
91    int maxEdgeId() const { return edges.size(); }  //FIXME: What is this?
92
93    Node tail(Edge e) const { return edges[e.n].tail; }
94    Node head(Edge e) const { return edges[e.n].head; }
95
96    NodeIt& first(NodeIt& v) const {
97      v=NodeIt(*this); return v; }
98    EdgeIt& first(EdgeIt& e) const {
99      e=EdgeIt(*this); return e; }
100    OutEdgeIt& first(OutEdgeIt& e, const Node v) const {
101      e=OutEdgeIt(*this,v); return e; }
102    InEdgeIt& first(InEdgeIt& e, const Node v) const {
103      e=InEdgeIt(*this,v); return e; }
104
105    static int id(Node v) { return v.n; }
106    static int id(Edge e) { return e.n; }
107
108    Node addNode() {
109      Node n; n.n=nodes.size();
110      nodes.push_back(NodeT()); //FIXME: Hmmm...
111
112     
113      node_maps.add(n);
114      return n;
115    }
116   
117    Edge addEdge(Node u, Node v) {
118      Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm...
119      edges[e.n].tail=u.n; edges[e.n].head=v.n;
120      edges[e.n].next_out=nodes[u.n].first_out;
121      edges[e.n].next_in=nodes[v.n].first_in;
122      nodes[u.n].first_out=nodes[v.n].first_in=e.n;
123
124      edge_maps.add(e);
125
126      return e;
127    }
128
129    /// Finds an edge between two nodes.
130
131    /// Finds an edge from node \c u to node \c v.
132    ///
133    /// If \c prev is \ref INVALID (this is the default value), then
134    /// It finds the first edge from \c u to \c v. Otherwise it looks for
135    /// the next edge from \c u to \c v after \c prev.
136    /// \return The found edge or INVALID if there is no such an edge.
137    Edge findEdge(Node u,Node v, Edge prev = INVALID)
138    {
139      int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;
140      while(e!=-1 && edges[e].tail!=v.n) e = edges[e].next_out;
141      prev.n=e;
142      return prev;
143    }
144   
145    void clear() {
146      edge_maps.clear();
147      edges.clear();
148      node_maps.clear();
149      nodes.clear();
150    }
151
152    class Node {
153      friend class SmartGraph;
154      template <typename T> friend class NodeMap;
155     
156      friend class Edge;
157      friend class OutEdgeIt;
158      friend class InEdgeIt;
159      friend class SymEdge;
160
161    protected:
162      int n;
163      friend int SmartGraph::id(Node v);
164      Node(int nn) {n=nn;}
165    public:
166      Node() {}
167      Node (Invalid) { n=-1; }
168      bool operator==(const Node i) const {return n==i.n;}
169      bool operator!=(const Node i) const {return n!=i.n;}
170      bool operator<(const Node i) const {return n<i.n;}
171      //      ///Validity check
172      //      operator bool() { return n!=-1; }
173    };
174   
175    class NodeIt : public Node {
176      const SmartGraph *G;
177      friend class SmartGraph;
178    public:
179      NodeIt() : Node() { }
180      NodeIt(const SmartGraph& _G,Node n) : Node(n), G(&_G) { }
181      NodeIt(Invalid i) : Node(i) { }
182      NodeIt(const SmartGraph& _G) : Node(_G.nodes.size()?0:-1), G(&_G) { }
183      NodeIt &operator++() {
184        n=(n+2)%(G->nodes.size()+1)-1;
185        return *this;
186      }
187//       ///Validity check
188//       operator bool() { return Node::operator bool(); }     
189    };
190
191    class Edge {
192      friend class SmartGraph;
193      template <typename T> friend class EdgeMap;
194
195      //template <typename T> friend class SymSmartGraph::SymEdgeMap;     
196      //friend Edge SymSmartGraph::opposite(Edge) const;
197     
198      friend class Node;
199      friend class NodeIt;
200    protected:
201      int n;
202      friend int SmartGraph::id(Edge e);
203
204    public:
205      /// An Edge with id \c n.
206
207      /// \bug It should be
208      /// obtained by a member function of the Graph.
209      Edge(int nn) {n=nn;}
210      Edge() { }
211      Edge (Invalid) { n=-1; }
212      bool operator==(const Edge i) const {return n==i.n;}
213      bool operator!=(const Edge i) const {return n!=i.n;}
214      bool operator<(const Edge i) const {return n<i.n;}
215      ///\bug This is a workaround until somebody tells me how to
216      ///make class \c SymSmartGraph::SymEdgeMap friend of Edge
217      int &idref() {return n;}
218      const int &idref() const {return n;}
219//       ///Validity check
220//       operator bool() { return n!=-1; }
221   };
222   
223    class EdgeIt : public Edge {
224      const SmartGraph *G;
225      friend class SmartGraph;
226    public:
227      EdgeIt(const SmartGraph& _G) : Edge(_G.edges.size()-1), G(&_G) { }
228      EdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }
229      EdgeIt (Invalid i) : Edge(i) { }
230      EdgeIt() : Edge() { }
231      ///\bug This is a workaround until somebody tells me how to
232      ///make class \c SymSmartGraph::SymEdgeMap friend of Edge
233      int &idref() {return n;}
234      EdgeIt &operator++() { --n; return *this; }
235//       ///Validity check
236//       operator bool() { return Edge::operator bool(); }     
237    };
238   
239    class OutEdgeIt : public Edge {
240      const SmartGraph *G;
241      friend class SmartGraph;
242    public:
243      OutEdgeIt() : Edge() { }
244      OutEdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }
245      OutEdgeIt (Invalid i) : Edge(i) { }
246
247      OutEdgeIt(const SmartGraph& _G,const Node v)
248        : Edge(_G.nodes[v.n].first_out), G(&_G) {}
249      OutEdgeIt &operator++() { n=G->edges[n].next_out; return *this; }
250//       ///Validity check
251//       operator bool() { return Edge::operator bool(); }     
252    };
253   
254    class InEdgeIt : public Edge {
255      const SmartGraph *G;
256      friend class SmartGraph;
257    public:
258      InEdgeIt() : Edge() { }
259      InEdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }
260      InEdgeIt (Invalid i) : Edge(i) { }
261      InEdgeIt(const SmartGraph& _G,Node v)
262        : Edge(_G.nodes[v.n].first_in), G(&_G) { }
263      InEdgeIt &operator++() { n=G->edges[n].next_in; return *this; }
264//       ///Validity check
265//       operator bool() { return Edge::operator bool(); }     
266    };
267
268  };
269
270  ///Graph for bidirectional edges.
271
272  ///The purpose of this graph structure is to handle graphs
273  ///having bidirectional edges. Here the function \c addEdge(u,v) adds a pair
274  ///of oppositely directed edges.
275  ///There is a new edge map type called
276  ///\ref SymSmartGraph::SymEdgeMap "SymEdgeMap"
277  ///that complements this
278  ///feature by
279  ///storing shared values for the edge pairs. The usual
280  ///\ref GraphSkeleton::EdgeMap "EdgeMap"
281  ///can be used
282  ///as well.
283  ///
284  ///The oppositely directed edge can also be obtained easily
285  ///using \ref opposite.
286  ///\warning It shares the similarity with \ref SmartGraph that
287  ///it is not possible to delete edges or nodes from the graph.
288  //\sa \ref SmartGraph.
289
290  class SymSmartGraph : public SmartGraph
291  {
292  public:
293    typedef SymSmartGraph Graph;
294
295    KEEP_NODE_MAP(SmartGraph);
296    KEEP_EDGE_MAP(SmartGraph);
297
298    CREATE_SYM_EDGE_MAP_REGISTRY;
299    CREATE_SYM_EDGE_MAP_FACTORY(DefaultMapFactory);
300    IMPORT_SYM_EDGE_MAP(SymEdgeMapFactory);
301
302    SymSmartGraph() : SmartGraph() { }
303    SymSmartGraph(const SmartGraph &_g) : SmartGraph(_g) { }
304    ///Adds a pair of oppositely directed edges to the graph.
305    Edge addEdge(Node u, Node v)
306    {
307      Edge e = SmartGraph::addEdge(u,v);
308      Edge f = SmartGraph::addEdge(v,u);
309      sym_edge_maps.add(e);
310      sym_edge_maps.add(f);
311      return e;
312    }
313
314    ///The oppositely directed edge.
315
316    ///Returns the oppositely directed
317    ///pair of the edge \c e.
318    static Edge opposite(Edge e)
319    {
320      Edge f;
321      f.idref() = e.idref() - 2*(e.idref()%2) + 1;
322      return f;
323    }
324   
325
326  };
327 
328  /// @} 
329} //namespace hugo
330
331
332
333
334#endif //HUGO_SMART_GRAPH_H
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