[150] | 1 | // -*- c++ -*- // |
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| 2 | #ifndef HUGO_KRUSKAL_H |
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| 3 | #define HUGO_KRUSKAL_H |
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| 4 | |
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| 5 | #include "unionfind.h" |
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| 6 | #include <algorithm> |
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| 7 | |
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| 8 | namespace hugo { |
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| 9 | |
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| 10 | |
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[218] | 11 | template <typename Graph, typename EdgeCostMap, typename EdgeBoolMap> |
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| 12 | class MinCostTreeKruskal |
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| 13 | { |
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[150] | 14 | |
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[218] | 15 | typedef typename Graph::EdgeIt EdgeIt; |
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| 16 | typedef typename Graph::Edge Edge; |
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[150] | 17 | |
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[218] | 18 | public: |
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| 19 | typedef typename EdgeCostMap::ValueType EdgeCost; |
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| 20 | typedef std::pair<Edge, EdgeCost> EdgeCostPair; |
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| 21 | typedef std::vector<EdgeCostPair> EdgeCostVector; |
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[150] | 22 | |
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[218] | 23 | private: |
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| 24 | Graph const &G; |
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| 25 | EdgeCostMap const &costmap; |
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| 26 | EdgeBoolMap& treemap; |
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| 27 | |
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| 28 | //template <typename EdgeCostPair> |
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| 29 | class comparePair { |
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| 30 | public: |
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| 31 | bool operator()(EdgeCostPair const& a, EdgeCostPair const& b) { |
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| 32 | return a.second < b.second; |
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| 33 | } |
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| 34 | }; |
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[150] | 35 | |
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[218] | 36 | public: |
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[150] | 37 | |
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| 38 | |
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[218] | 39 | MinCostTreeKruskal(Graph const& _G, EdgeCostMap const& _costmap, |
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| 40 | EdgeBoolMap& _treemap) : G(_G), costmap(_costmap), |
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| 41 | treemap(_treemap) {} |
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| 42 | |
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| 43 | |
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| 44 | EdgeCost run() |
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| 45 | { |
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| 46 | EdgeCostVector rank; |
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| 47 | for (EdgeIt e=G.template first<EdgeIt>(); G.valid(e); G.next(e)) { |
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| 48 | rank.push_back(make_pair(e, costmap.get(e))); |
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| 49 | } |
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| 50 | |
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| 51 | std::sort(rank.begin(), rank.end(), comparePair()); |
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| 52 | |
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| 53 | return run(rank); |
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| 54 | |
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[150] | 55 | } |
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| 56 | |
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[218] | 57 | EdgeCost run(EdgeCostVector const &rank) |
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| 58 | { |
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| 59 | typedef typename Graph::NodeMap<int> NodeIntMap; |
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| 60 | typedef typename Graph::Node Node; |
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| 61 | NodeIntMap comp_map(G, -1); |
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| 62 | UnionFind<Node,NodeIntMap> uf(comp_map); |
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| 63 | |
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| 64 | EdgeCost tot_cost = 0; |
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| 65 | for (typename EdgeCostVector::const_iterator p = rank.begin(); |
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| 66 | p!=rank.end(); ++p ) { |
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| 67 | if ( uf.joinComponents(G.head(p->first), G.tail(p->first)) ) { |
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| 68 | treemap.set(p->first, true); |
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| 69 | tot_cost += p->second; |
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| 70 | } |
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| 71 | else { |
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| 72 | treemap.set(p->first, false); |
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| 73 | } |
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| 74 | } |
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| 75 | return tot_cost; |
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[150] | 76 | |
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[218] | 77 | } |
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[150] | 78 | |
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[218] | 79 | }; |
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[150] | 80 | |
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| 81 | |
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| 82 | } //namespace hugo |
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| 83 | |
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| 84 | #endif //HUGO_KRUSKAL_H |
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