COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/smart_graph.h @ 921:818510fa3d99

Last change on this file since 921:818510fa3d99 was 921:818510fa3d99, checked in by Alpar Juttner, 16 years ago

hugo -> lemon

File size: 10.1 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/smart_graph.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#ifndef LEMON_SMART_GRAPH_H
18#define LEMON_SMART_GRAPH_H
19
20///\ingroup graphs
21///\file
22///\brief SmartGraph and SymSmartGraph classes.
23
24#include <vector>
25#include <climits>
26
27#include <lemon/invalid.h>
28
29#include <lemon/array_map.h>
30#include <lemon/sym_map.h>
31
32#include <lemon/map_registry.h>
33
34#include <lemon/map_defines.h>
35
36namespace lemon {
37
38/// \addtogroup graphs
39/// @{
40//  class SymSmartGraph;
41
42  ///A smart graph class.
43
44  ///This is a simple and fast graph implementation.
45  ///It is also quite memory efficient, but at the price
46  ///that <b> it does not support node and edge deletion</b>.
47  ///It conforms to
48  ///the \ref skeleton::ExtendableGraph "ExtendableGraph" concept.
49  ///\sa skeleton::ExtendableGraph.
50  ///
51  ///\todo Some member functions could be \c static.
52  ///
53  ///\todo A possibly useful functionality: a function saveState() would
54  ///give back a data sturcture X and then the function restoreState(X)
55  ///would remove the nodes and edges added after the call of saveState().
56  ///Of course it should be used as a stack. (Maybe X is not necessary.)
57  ///
58  ///\author Alpar Juttner
59  class SmartGraph {
60
61    struct NodeT
62    {
63      int first_in,first_out;     
64      NodeT() : first_in(-1), first_out(-1) {}
65    };
66    struct EdgeT
67    {
68      int head, tail, next_in, next_out;     
69      //FIXME: is this necessary?
70      EdgeT() : next_in(-1), next_out(-1) {} 
71    };
72
73    std::vector<NodeT> nodes;
74
75    std::vector<EdgeT> edges;
76   
77   
78  public:
79
80    typedef SmartGraph Graph;
81
82    class Node;
83    class Edge;
84
85    class NodeIt;
86    class EdgeIt;
87    class OutEdgeIt;
88    class InEdgeIt;
89   
90    // Create map registries.
91    CREATE_MAP_REGISTRIES;
92    // Create node and edge maps.
93    CREATE_MAPS(ArrayMap);
94   
95  public:
96
97    SmartGraph() : nodes(), edges() { }
98    SmartGraph(const SmartGraph &_g) : nodes(_g.nodes), edges(_g.edges) { }
99   
100    ///Number of nodes.
101    int nodeNum() const { return nodes.size(); }
102    ///Number of edges.
103    int edgeNum() const { return edges.size(); }
104
105    /// Maximum node ID.
106   
107    /// Maximum node ID.
108    ///\sa id(Node)
109    int maxNodeId() const { return nodes.size()-1; }
110    /// Maximum edge ID.
111   
112    /// Maximum edge ID.
113    ///\sa id(Edge)
114    int maxEdgeId() const { return edges.size()-1; }
115
116    Node tail(Edge e) const { return edges[e.n].tail; }
117    Node head(Edge e) const { return edges[e.n].head; }
118
119    NodeIt& first(NodeIt& v) const {
120      v=NodeIt(*this); return v; }
121    EdgeIt& first(EdgeIt& e) const {
122      e=EdgeIt(*this); return e; }
123    OutEdgeIt& first(OutEdgeIt& e, const Node v) const {
124      e=OutEdgeIt(*this,v); return e; }
125    InEdgeIt& first(InEdgeIt& e, const Node v) const {
126      e=InEdgeIt(*this,v); return e; }
127
128    /// Node ID.
129   
130    /// The ID of a valid Node is a nonnegative integer not greater than
131    /// \ref maxNodeId(). The range of the ID's is not surely continuous
132    /// and the greatest node ID can be actually less then \ref maxNodeId().
133    ///
134    /// The ID of the \ref INVALID node is -1.
135    ///\return The ID of the node \c v.
136    static int id(Node v) { return v.n; }
137    /// Edge ID.
138   
139    /// The ID of a valid Edge is a nonnegative integer not greater than
140    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
141    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
142    ///
143    /// The ID of the \ref INVALID edge is -1.
144    ///\return The ID of the edge \c e.
145    static int id(Edge e) { return e.n; }
146
147    Node addNode() {
148      Node n; n.n=nodes.size();
149      nodes.push_back(NodeT()); //FIXME: Hmmm...
150
151     
152      node_maps.add(n);
153      return n;
154    }
155   
156    Edge addEdge(Node u, Node v) {
157      Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm...
158      edges[e.n].tail=u.n; edges[e.n].head=v.n;
159      edges[e.n].next_out=nodes[u.n].first_out;
160      edges[e.n].next_in=nodes[v.n].first_in;
161      nodes[u.n].first_out=nodes[v.n].first_in=e.n;
162
163      edge_maps.add(e);
164
165      return e;
166    }
167
168    /// Finds an edge between two nodes.
169
170    /// Finds an edge from node \c u to node \c v.
171    ///
172    /// If \c prev is \ref INVALID (this is the default value), then
173    /// It finds the first edge from \c u to \c v. Otherwise it looks for
174    /// the next edge from \c u to \c v after \c prev.
175    /// \return The found edge or INVALID if there is no such an edge.
176    Edge findEdge(Node u,Node v, Edge prev = INVALID)
177    {
178      int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;
179      while(e!=-1 && edges[e].tail!=v.n) e = edges[e].next_out;
180      prev.n=e;
181      return prev;
182    }
183   
184    void clear() {
185      edge_maps.clear();
186      edges.clear();
187      node_maps.clear();
188      nodes.clear();
189    }
190
191    class Node {
192      friend class SmartGraph;
193      template <typename T> friend class NodeMap;
194     
195      friend class Edge;
196      friend class OutEdgeIt;
197      friend class InEdgeIt;
198      friend class SymEdge;
199
200    protected:
201      int n;
202      friend int SmartGraph::id(Node v);
203      Node(int nn) {n=nn;}
204    public:
205      Node() {}
206      Node (Invalid) { n=-1; }
207      bool operator==(const Node i) const {return n==i.n;}
208      bool operator!=(const Node i) const {return n!=i.n;}
209      bool operator<(const Node i) const {return n<i.n;}
210      //      ///Validity check
211      //      operator bool() { return n!=-1; }
212    };
213   
214    class NodeIt : public Node {
215      const SmartGraph *G;
216      friend class SmartGraph;
217    public:
218      NodeIt() : Node() { }
219      NodeIt(const SmartGraph& _G,Node n) : Node(n), G(&_G) { }
220      NodeIt(Invalid i) : Node(i) { }
221      NodeIt(const SmartGraph& _G) : Node(_G.nodes.size()?0:-1), G(&_G) { }
222      NodeIt &operator++() {
223        n=(n+2)%(G->nodes.size()+1)-1;
224        return *this;
225      }
226//       ///Validity check
227//       operator bool() { return Node::operator bool(); }     
228    };
229
230    class Edge {
231      friend class SmartGraph;
232      template <typename T> friend class EdgeMap;
233
234      friend class SymSmartGraph;
235     
236      friend class Node;
237      friend class NodeIt;
238    protected:
239      int n;
240      friend int SmartGraph::id(Edge e);
241      Edge(int nn) {n=nn;}
242    public:
243      /// An Edge with id \c n.
244
245      Edge() { }
246      Edge (Invalid) { n=-1; }
247      bool operator==(const Edge i) const {return n==i.n;}
248      bool operator!=(const Edge i) const {return n!=i.n;}
249      bool operator<(const Edge i) const {return n<i.n;}
250//       ///Validity check
251//       operator bool() { return n!=-1; }
252
253      ///Set the edge to that have ID \c ID.
254      void setToId(int id) { n=id; }
255   };
256   
257    class EdgeIt : public Edge {
258      const SmartGraph *G;
259      friend class SmartGraph;
260    public:
261      EdgeIt(const SmartGraph& _G) : Edge(_G.edges.size()-1), G(&_G) { }
262      EdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }
263      EdgeIt (Invalid i) : Edge(i) { }
264      EdgeIt() : Edge() { }
265      EdgeIt &operator++() { --n; return *this; }
266//       ///Validity check
267//       operator bool() { return Edge::operator bool(); }     
268    };
269   
270    class OutEdgeIt : public Edge {
271      const SmartGraph *G;
272      friend class SmartGraph;
273    public:
274      OutEdgeIt() : Edge() { }
275      OutEdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }
276      OutEdgeIt (Invalid i) : Edge(i) { }
277
278      OutEdgeIt(const SmartGraph& _G,const Node v)
279        : Edge(_G.nodes[v.n].first_out), G(&_G) {}
280      OutEdgeIt &operator++() { n=G->edges[n].next_out; return *this; }
281//       ///Validity check
282//       operator bool() { return Edge::operator bool(); }     
283    };
284   
285    class InEdgeIt : public Edge {
286      const SmartGraph *G;
287      friend class SmartGraph;
288    public:
289      InEdgeIt() : Edge() { }
290      InEdgeIt(const SmartGraph& _G, Edge e) : Edge(e), G(&_G) { }
291      InEdgeIt (Invalid i) : Edge(i) { }
292      InEdgeIt(const SmartGraph& _G,Node v)
293        : Edge(_G.nodes[v.n].first_in), G(&_G) { }
294      InEdgeIt &operator++() { n=G->edges[n].next_in; return *this; }
295//       ///Validity check
296//       operator bool() { return Edge::operator bool(); }     
297    };
298
299  };
300
301  ///Graph for bidirectional edges.
302
303  ///The purpose of this graph structure is to handle graphs
304  ///having bidirectional edges. Here the function \c addEdge(u,v) adds a pair
305  ///of oppositely directed edges.
306  ///There is a new edge map type called
307  ///\ref SymSmartGraph::SymEdgeMap "SymEdgeMap"
308  ///that complements this
309  ///feature by
310  ///storing shared values for the edge pairs. The usual
311  ///\ref Graph::EdgeMap "EdgeMap"
312  ///can be used
313  ///as well.
314  ///
315  ///The oppositely directed edge can also be obtained easily
316  ///using \ref opposite.
317  ///\warning It shares the similarity with \ref SmartGraph that
318  ///it is not possible to delete edges or nodes from the graph.
319  //\sa SmartGraph.
320
321  class SymSmartGraph : public SmartGraph
322  {
323  public:
324    typedef SymSmartGraph Graph;
325
326    // Create symmetric map registry.
327    CREATE_SYM_EDGE_MAP_REGISTRY;
328    // Create symmetric edge map.
329    CREATE_SYM_EDGE_MAP(ArrayMap);
330
331
332    SymSmartGraph() : SmartGraph() { }
333    SymSmartGraph(const SmartGraph &_g) : SmartGraph(_g) { }
334    ///Adds a pair of oppositely directed edges to the graph.
335    Edge addEdge(Node u, Node v)
336    {
337      Edge e = SmartGraph::addEdge(u,v);
338      Edge f = SmartGraph::addEdge(v,u);
339      sym_edge_maps.add(e);
340      sym_edge_maps.add(f);
341      return e;
342    }
343
344    ///The oppositely directed edge.
345
346    ///Returns the oppositely directed
347    ///pair of the edge \c e.
348    static Edge opposite(Edge e)
349    {
350      Edge f;
351      f.n = e.n - 2*(e.n%2) + 1;
352      return f;
353    }
354   
355
356  };
357 
358  /// @} 
359} //namespace lemon
360
361
362
363
364#endif //LEMON_SMART_GRAPH_H
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