[455] | 1 | // -*- c++ -*- |
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[921] | 2 | #ifndef LEMON_BFS_DFS_MISC_H |
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| 3 | #define LEMON_BFS_DFS_MISC_H |
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[455] | 4 | |
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[615] | 5 | /// \ingroup galgs |
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| 6 | /// \file |
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| 7 | /// \brief Miscellaneous algorithms using bfs and dfs. |
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[604] | 8 | /// |
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[615] | 9 | /// This file contains several algorithms using bfs and dfs. |
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[604] | 10 | /// |
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| 11 | // ///\author Marton Makai |
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| 12 | |
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[602] | 13 | #include <bfs_dfs.h> |
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[762] | 14 | #include <for_each_macros.h> |
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[455] | 15 | |
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[921] | 16 | namespace lemon { |
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[455] | 17 | |
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[615] | 18 | /// This function eats a read-write \c BoolMap& bool_map, |
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[455] | 19 | /// which have to work well up |
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| 20 | /// to its \c set and \c operator[]() method. Thus we have to deal |
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| 21 | /// very carefully with an uninitialized \c IterableBoolMap. |
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[615] | 22 | /// \ingroup galgs |
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[455] | 23 | template<typename Graph, typename BoolMap> |
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| 24 | bool isBipartite(const Graph& g, BoolMap& bool_map) { |
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| 25 | typedef typename Graph::template NodeMap<bool> ReachedMap; |
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| 26 | ReachedMap reached(g/*, false*/); |
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| 27 | BfsIterator<Graph, ReachedMap> bfs(g, reached); |
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| 28 | FOR_EACH_LOC(typename Graph::NodeIt, n, g) { |
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| 29 | if (!reached[n]) { |
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| 30 | bfs.pushAndSetReached(n); |
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[549] | 31 | bool_map.set(n, false); |
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| 32 | while (!bfs.finished()) { |
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| 33 | if (bfs.isBNodeNewlyReached()) { |
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| 34 | bool_map.set(bfs.bNode())=!bfs.aNode(); |
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| 35 | } else { |
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| 36 | if (bool_map[bfs.bNode()]==bool_map[bfs.aNode()]) { |
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| 37 | return false; |
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[455] | 38 | } |
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| 39 | } |
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[549] | 40 | ++bfs; |
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[455] | 41 | } |
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| 42 | } |
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| 43 | } |
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[549] | 44 | |
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[455] | 45 | return true; |
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| 46 | } |
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[540] | 47 | |
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| 48 | /// experimental topsort, |
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| 49 | /// I think the final version will work as an iterator |
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[549] | 50 | /// if the graph is not a acyclic, the na pre-topological order is obtained |
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[577] | 51 | /// (see Schrijver's book). |
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| 52 | /// PredMap have to be a writtable node-map. |
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| 53 | /// If the graph is directed and not acyclic, |
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| 54 | /// then going back from the returned node via the pred information, a |
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| 55 | /// cycle is obtained. |
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[615] | 56 | /// \ingroup galgs |
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[577] | 57 | template<typename Graph, typename PredMap> |
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| 58 | typename Graph::Node |
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| 59 | topSort(const Graph& g, std::list<typename Graph::Node>& l, |
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| 60 | PredMap& pred) { |
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[540] | 61 | l.clear(); |
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| 62 | typedef typename Graph::template NodeMap<bool> ReachedMap; |
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[577] | 63 | typedef typename Graph::template NodeMap<bool> ExaminedMap; |
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[540] | 64 | ReachedMap reached(g/*, false*/); |
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[577] | 65 | ExaminedMap examined(g/*, false*/); |
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[540] | 66 | DfsIterator<Graph, ReachedMap> dfs(g, reached); |
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| 67 | FOR_EACH_LOC(typename Graph::NodeIt, n, g) { |
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| 68 | if (!reached[n]) { |
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| 69 | dfs.pushAndSetReached(n); |
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[577] | 70 | pred.set(n, INVALID); |
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[543] | 71 | while (!dfs.finished()) { |
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[552] | 72 | ++dfs; |
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[577] | 73 | if (dfs.isBNodeNewlyReached()) { |
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[921] | 74 | ///\bug lemon 0.2-ben Edge kell |
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[577] | 75 | pred.set(dfs.aNode(), typename Graph::OutEdgeIt(dfs)); |
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| 76 | } else { |
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| 77 | ///\bug ugyanaz |
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| 78 | if (g.valid(typename Graph::OutEdgeIt(dfs)) && |
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| 79 | !examined[dfs.bNode()]) { |
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[921] | 80 | ///\bug lemon 0.2-ben Edge kell |
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[577] | 81 | pred.set(dfs.bNode(), typename Graph::OutEdgeIt(dfs)); |
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| 82 | return dfs.aNode(); |
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| 83 | } |
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| 84 | } |
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[543] | 85 | if (dfs.isANodeExamined()) { |
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| 86 | l.push_back(dfs.aNode()); |
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[577] | 87 | examined.set(dfs.aNode(), true); |
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[540] | 88 | } |
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| 89 | } |
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| 90 | } |
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| 91 | } |
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[577] | 92 | return INVALID; |
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[540] | 93 | } |
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[615] | 94 | |
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[921] | 95 | } //namespace lemon |
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[548] | 96 | |
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[921] | 97 | #endif //LEMON_BFS_DFS_MISC_H |
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