# source:lemon-0.x/src/work/marci/bfs_dfs_misc.h@555:995bc1f1a3ce

Last change on this file since 555:995bc1f1a3ce was 552:83c22ca968d8, checked in by marci, 17 years ago

top-sort, for fezso's sake

File size: 1.7 KB
Line
1// -*- c++ -*-
2#ifndef HUGO_BFS_DFS_MISC_H
3#define HUGO_BFS_DFS_MISC_H
4
5#include <bfs_iterator.h>
6#include <for_each_macros.h>
7
8namespace hugo {
9
10  /// This function eat a read-write \c BoolMap& bool_map,
11  /// which have to work well up
12  /// to its \c set and \c operator[]() method. Thus we have to deal
13  /// very carefully with an uninitialized \c IterableBoolMap.
14  template<typename Graph, typename BoolMap>
15  bool isBipartite(const Graph& g, BoolMap& bool_map) {
16    typedef typename Graph::template NodeMap<bool> ReachedMap;
17    ReachedMap reached(g/*, false*/);
18    BfsIterator<Graph, ReachedMap> bfs(g, reached);
19    FOR_EACH_LOC(typename Graph::NodeIt, n, g) {
20      if (!reached[n]) {
21        bfs.pushAndSetReached(n);
22        bool_map.set(n, false);
23        while (!bfs.finished()) {
24          if (bfs.isBNodeNewlyReached()) {
25            bool_map.set(bfs.bNode())=!bfs.aNode();
26          } else {
27            if (bool_map[bfs.bNode()]==bool_map[bfs.aNode()]) {
28              return false;
29            }
30          }
31          ++bfs;
32        }
33      }
34    }
35
36    return true;
37  }
38
39  /// experimental topsort,
40  /// I think the final version will work as an iterator
41  /// if the graph is not a acyclic, the na pre-topological order is obtained
42  /// (see Schrijver's book)
43  template<typename Graph>
44  void topSort(const Graph& g, std::list<typename Graph::Node>& l) {
45    l.clear();
46    typedef typename Graph::template NodeMap<bool> ReachedMap;
47    ReachedMap reached(g/*, false*/);
48    DfsIterator<Graph, ReachedMap> dfs(g, reached);
49    FOR_EACH_LOC(typename Graph::NodeIt, n, g) {
50      if (!reached[n]) {
51        dfs.pushAndSetReached(n);
52        while (!dfs.finished()) {
53          ++dfs;
54          if (dfs.isANodeExamined()) {
55            l.push_back(dfs.aNode());
56          }
57        }
58      }
59    }
60  }
61} //namespace hugo
62
63#endif //HUGO_BFS_DFS_MISC_H
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