COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/smart_graph.h @ 969:0631847b37e5

Last change on this file since 969:0631847b37e5 was 969:0631847b37e5, checked in by Alpar Juttner, 16 years ago

findEdge() declaration went to the right place (for the sake of Doxygen.)

File size: 7.4 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
26#include <lemon/invalid.h>
27
28#include <lemon/erasable_graph_extender.h>
29#include <lemon/clearable_graph_extender.h>
30#include <lemon/extendable_graph_extender.h>
31
32#include <lemon/idmappable_graph_extender.h>
33
34#include <lemon/iterable_graph_extender.h>
35
36#include <lemon/alteration_observer_registry.h>
37#include <lemon/default_map.h>
38
39
40#include <lemon/graph_utils.h>
41
42
43namespace lemon {
44
45  /// \addtogroup graphs
46  /// @{
47
48  ///Base of SmartGraph
49
50  ///Base of SmartGraph
51  ///
52  class SmartGraphBase {
53
54    struct NodeT
55    {
56      int first_in,first_out;     
57      NodeT() : first_in(-1), first_out(-1) {}
58    };
59    struct EdgeT
60    {
61      int head, tail, next_in, next_out;     
62      //FIXME: is this necessary?
63      EdgeT() : next_in(-1), next_out(-1) {} 
64    };
65
66    std::vector<NodeT> nodes;
67
68    std::vector<EdgeT> edges;
69   
70   
71  public:
72
73    typedef SmartGraphBase Graph;
74
75    class Node;
76    class Edge;
77
78   
79  public:
80
81    SmartGraphBase() : nodes(), edges() { }
82    SmartGraphBase(const SmartGraphBase &_g) : nodes(_g.nodes), edges(_g.edges) { }
83   
84    ///Number of nodes.
85    int nodeNum() const { return nodes.size(); }
86    ///Number of edges.
87    int edgeNum() const { return edges.size(); }
88
89    /// Maximum node ID.
90   
91    /// Maximum node ID.
92    ///\sa id(Node)
93    int maxNodeId() const { return nodes.size()-1; }
94    /// Maximum edge ID.
95   
96    /// Maximum edge ID.
97    ///\sa id(Edge)
98    int maxEdgeId() const { return edges.size()-1; }
99
100    Node tail(Edge e) const { return edges[e.n].tail; }
101    Node head(Edge e) const { return edges[e.n].head; }
102
103    /// Node ID.
104   
105    /// The ID of a valid Node is a nonnegative integer not greater than
106    /// \ref maxNodeId(). The range of the ID's is not surely continuous
107    /// and the greatest node ID can be actually less then \ref maxNodeId().
108    ///
109    /// The ID of the \ref INVALID node is -1.
110    ///\return The ID of the node \c v.
111    static int id(Node v) { return v.n; }
112    /// Edge ID.
113   
114    /// The ID of a valid Edge is a nonnegative integer not greater than
115    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
116    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
117    ///
118    /// The ID of the \ref INVALID edge is -1.
119    ///\return The ID of the edge \c e.
120    static int id(Edge e) { return e.n; }
121
122    Node addNode() {
123      Node n; n.n=nodes.size();
124      nodes.push_back(NodeT()); //FIXME: Hmmm...
125      return n;
126    }
127   
128    Edge addEdge(Node u, Node v) {
129      Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm...
130      edges[e.n].tail=u.n; edges[e.n].head=v.n;
131      edges[e.n].next_out=nodes[u.n].first_out;
132      edges[e.n].next_in=nodes[v.n].first_in;
133      nodes[u.n].first_out=nodes[v.n].first_in=e.n;
134
135      return e;
136    }
137
138    void clear() {
139      edges.clear();
140      nodes.clear();
141    }
142
143
144    class Node {
145      friend class SmartGraphBase;
146
147    protected:
148      int n;
149      Node(int nn) {n=nn;}
150    public:
151      Node() {}
152      Node (Invalid) { n=-1; }
153      bool operator==(const Node i) const {return n==i.n;}
154      bool operator!=(const Node i) const {return n!=i.n;}
155      bool operator<(const Node i) const {return n<i.n;}
156    };
157   
158
159    class Edge {
160      friend class SmartGraphBase;
161
162    protected:
163      int n;
164      Edge(int nn) {n=nn;}
165    public:
166      Edge() { }
167      Edge (Invalid) { n=-1; }
168      bool operator==(const Edge i) const {return n==i.n;}
169      bool operator!=(const Edge i) const {return n!=i.n;}
170      bool operator<(const Edge i) const {return n<i.n;}
171    };
172
173    void first(Node& node) const {
174      node.n = nodes.size() - 1;
175    }
176
177    static void next(Node& node) {
178      --node.n;
179    }
180
181    void first(Edge& edge) const {
182      edge.n = edges.size() - 1;
183    }
184
185    static void next(Edge& edge) {
186      --edge.n;
187    }
188
189    void firstOut(Edge& edge, const Node& node) const {
190      edge.n = nodes[node.n].first_out;
191    }
192
193    void nextOut(Edge& edge) const {
194      edge.n = edges[edge.n].next_out;
195    }
196
197    void firstIn(Edge& edge, const Node& node) const {
198      edge.n = nodes[node.n].first_in;
199    }
200   
201    void nextIn(Edge& edge) const {
202      edge.n = edges[edge.n].next_in;
203    }
204
205    Edge _findEdge(Node u,Node v, Edge prev = INVALID)
206    {
207      int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;
208      while(e!=-1 && edges[e].tail!=v.n) e = edges[e].next_out;
209      prev.n=e;
210      return prev;
211    }
212  };
213
214  typedef AlterableGraphExtender<SmartGraphBase> AlterableSmartGraphBase;
215  typedef IterableGraphExtender<AlterableSmartGraphBase> IterableSmartGraphBase;
216  typedef IdMappableGraphExtender<IterableSmartGraphBase> IdMappableSmartGraphBase;
217  typedef DefaultMappableGraphExtender<IdMappableSmartGraphBase> MappableSmartGraphBase;
218  typedef ExtendableGraphExtender<MappableSmartGraphBase> ExtendableSmartGraphBase;
219  typedef ClearableGraphExtender<ExtendableSmartGraphBase> ClearableSmartGraphBase;
220
221  ///A smart graph class.
222
223  ///This is a simple and fast graph implementation.
224  ///It is also quite memory efficient, but at the price
225  ///that <b> it does not support node and edge deletion</b>.
226  ///It conforms to
227  ///the \ref concept::ExtendableGraph "ExtendableGraph" concept.
228  ///\sa concept::ExtendableGraph.
229  ///
230  ///\todo Some member functions could be \c static.
231  ///
232  ///\todo A possibly useful functionality: a function saveState()
233  ///(or snapshot() ) would
234  ///give back a data sturcture X and then the function restoreState(X)
235  ///(or rollBack() )
236  ///would remove the nodes and edges added after the call of saveState().
237  ///Of course it should be used as a stack. (Maybe X is not necessary.)
238  ///
239  ///\author Alpar Juttner
240  class SmartGraph :public ClearableSmartGraphBase {
241  public:
242    /// Finds an edge between two nodes.
243
244    /// Finds an edge from node \c u to node \c v.
245    ///
246    /// If \c prev is \ref INVALID (this is the default value), then
247    /// it finds the first edge from \c u to \c v. Otherwise it looks for
248    /// the next edge from \c u to \c v after \c prev.
249    /// \return The found edge or \ref INVALID if there is no such an edge.
250    ///
251    /// Thus you can iterate through each edge from \c u to \c v as it follows.
252    /// \code
253    /// for(Edge e=G.findEdge(u,v);e!=INVALID;e=G.findEdge(u,v,e)) {
254    ///   ...
255    /// }
256    /// \endcode
257    /// \todo Possibly it should be a global function.
258    Edge findEdge(Node u,Node v, Edge prev = INVALID)
259    {
260      return _findEdge(u,v,prev);
261    }
262};
263 
264  template <>
265  int countNodes<SmartGraph>(const SmartGraph& graph) {
266    return graph.nodeNum();
267  }
268
269  template <>
270  int countEdges<SmartGraph>(const SmartGraph& graph) {
271    return graph.edgeNum();
272  }
273
274  /// @} 
275} //namespace lemon
276
277
278
279
280#endif //LEMON_SMART_GRAPH_H
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