1 | // -*- c++ -*- |
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2 | #ifndef HUGO_BFS_DFS_MISC_H |
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3 | #define HUGO_BFS_DFS_MISC_H |
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4 | |
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5 | #include <bfs_iterator.h> |
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6 | #include <for_each_macros.h> |
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7 | |
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8 | namespace hugo { |
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9 | |
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10 | /// This function eat a read-write \c BoolMap& bool_map, |
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11 | /// which have to work well up |
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12 | /// to its \c set and \c operator[]() method. Thus we have to deal |
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13 | /// very carefully with an uninitialized \c IterableBoolMap. |
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14 | template<typename Graph, typename BoolMap> |
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15 | bool isBipartite(const Graph& g, BoolMap& bool_map) { |
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16 | typedef typename Graph::template NodeMap<bool> ReachedMap; |
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17 | ReachedMap reached(g/*, false*/); |
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18 | BfsIterator<Graph, ReachedMap> bfs(g, reached); |
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19 | FOR_EACH_LOC(typename Graph::NodeIt, n, g) { |
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20 | if (!reached[n]) { |
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21 | bfs.pushAndSetReached(n); |
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22 | bool_map.set(n, false); |
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23 | while (!bfs.finished()) { |
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24 | if (bfs.isBNodeNewlyReached()) { |
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25 | bool_map.set(bfs.bNode())=!bfs.aNode(); |
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26 | } else { |
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27 | if (bool_map[bfs.bNode()]==bool_map[bfs.aNode()]) { |
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28 | return false; |
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29 | } |
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30 | } |
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31 | ++bfs; |
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32 | } |
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33 | } |
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34 | } |
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35 | |
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36 | return true; |
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37 | } |
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38 | |
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39 | /// experimental topsort, |
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40 | /// I think the final version will work as an iterator |
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41 | /// if the graph is not a acyclic, the na pre-topological order is obtained |
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42 | /// (see Schrijver's book). |
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43 | /// PredMap have to be a writtable node-map. |
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44 | /// If the graph is directed and not acyclic, |
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45 | /// then going back from the returned node via the pred information, a |
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46 | /// cycle is obtained. |
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47 | template<typename Graph, typename PredMap> |
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48 | typename Graph::Node |
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49 | topSort(const Graph& g, std::list<typename Graph::Node>& l, |
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50 | PredMap& pred) { |
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51 | l.clear(); |
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52 | typedef typename Graph::template NodeMap<bool> ReachedMap; |
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53 | typedef typename Graph::template NodeMap<bool> ExaminedMap; |
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54 | ReachedMap reached(g/*, false*/); |
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55 | ExaminedMap examined(g/*, false*/); |
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56 | DfsIterator<Graph, ReachedMap> dfs(g, reached); |
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57 | FOR_EACH_LOC(typename Graph::NodeIt, n, g) { |
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58 | if (!reached[n]) { |
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59 | dfs.pushAndSetReached(n); |
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60 | pred.set(n, INVALID); |
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61 | while (!dfs.finished()) { |
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62 | ++dfs; |
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63 | if (dfs.isBNodeNewlyReached()) { |
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64 | ///\bug hugo 0.2-ben Edge kell |
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65 | pred.set(dfs.aNode(), typename Graph::OutEdgeIt(dfs)); |
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66 | } else { |
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67 | ///\bug ugyanaz |
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68 | if (g.valid(typename Graph::OutEdgeIt(dfs)) && |
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69 | !examined[dfs.bNode()]) { |
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70 | ///\bug hugo 0.2-ben Edge kell |
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71 | pred.set(dfs.bNode(), typename Graph::OutEdgeIt(dfs)); |
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72 | return dfs.aNode(); |
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73 | } |
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74 | } |
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75 | if (dfs.isANodeExamined()) { |
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76 | l.push_back(dfs.aNode()); |
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77 | examined.set(dfs.aNode(), true); |
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78 | } |
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79 | } |
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80 | } |
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81 | } |
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82 | return INVALID; |
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83 | } |
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84 | } //namespace hugo |
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85 | |
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86 | #endif //HUGO_BFS_DFS_MISC_H |
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