[1199] | 1 | #ifndef LEMON_OPT2_TSP_H |
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| 2 | #define LEMON_OPT2_TSP_H |
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| 3 | |
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| 4 | #include <vector> |
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| 5 | #include <lemon/full_graph.h> |
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| 6 | #include <lemon/path.h> |
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| 7 | |
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| 8 | namespace lemon { |
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| 9 | |
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| 10 | namespace opt2_helper { |
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| 11 | template <class L> |
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| 12 | L vectorConvert(const std::vector<FullGraph::Node> &_path) { |
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| 13 | return L(_path.begin(), _path.end()); |
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| 14 | } |
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| 15 | |
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| 16 | template <> |
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| 17 | std::vector<FullGraph::Node> vectorConvert(const std::vector<FullGraph::Node> &_path) { |
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| 18 | return _path; |
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| 19 | } |
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| 20 | } |
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| 21 | |
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| 22 | template <typename CM> |
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| 23 | class Opt2Tsp { |
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| 24 | private: |
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| 25 | GRAPH_TYPEDEFS(FullGraph); |
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| 26 | |
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| 27 | public: |
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| 28 | typedef CM CostMap; |
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| 29 | typedef typename CM::Value Cost; |
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| 30 | |
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| 31 | |
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| 32 | Opt2Tsp(const FullGraph &gr, const CostMap &cost) : _gr(gr), _cost(cost), |
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| 33 | tmppath(_gr.nodeNum()*2) { |
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| 34 | |
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| 35 | for (int i=1; i<_gr.nodeNum()-1; ++i) { |
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| 36 | tmppath[2*i] = i-1; |
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| 37 | tmppath[2*i+1] = i+1; |
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| 38 | } |
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| 39 | tmppath[0] = _gr.nodeNum()-1; |
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| 40 | tmppath[1] = 1; |
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| 41 | tmppath[2*(_gr.nodeNum()-1)] = _gr.nodeNum()-2; |
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| 42 | tmppath[2*(_gr.nodeNum()-1)+1] = 0; |
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| 43 | } |
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| 44 | |
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| 45 | Opt2Tsp(const FullGraph &gr, const CostMap &cost, const std::vector<Node> &path) : |
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| 46 | _gr(gr), _cost(cost), tmppath(_gr.nodeNum()*2) { |
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| 47 | |
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| 48 | for (unsigned int i=1; i<path.size()-1; ++i) { |
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| 49 | tmppath[2*_gr.id(path[i])] = _gr.id(path[i-1]); |
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| 50 | tmppath[2*_gr.id(path[i])+1] = _gr.id(path[i+1]); |
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| 51 | } |
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| 52 | |
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| 53 | tmppath[2*_gr.id(path[0])] = _gr.id(path.back()); |
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| 54 | tmppath[2*_gr.id(path[0])+1] = _gr.id(path[1]); |
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| 55 | tmppath[2*_gr.id(path.back())] = _gr.id(path[path.size()-2]); |
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| 56 | tmppath[2*_gr.id(path.back())+1] = _gr.id(path.front()); |
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| 57 | } |
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| 58 | |
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| 59 | private: |
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| 60 | Cost c(int u, int v) { |
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| 61 | return _cost[_gr.edge(_gr.nodeFromId(u), _gr.nodeFromId(v))]; |
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| 62 | } |
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| 63 | |
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| 64 | class It { |
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| 65 | public: |
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| 66 | It(const std::vector<int> &path, int i=0) : tmppath(path), act(i), last(tmppath[2*act]) {} |
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| 67 | It(const std::vector<int> &path, int i, int l) : tmppath(path), act(i), last(l) {} |
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| 68 | |
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| 69 | int next_index() const { |
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| 70 | return (tmppath[2*act]==last)? 2*act+1 : 2*act; |
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| 71 | } |
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| 72 | |
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| 73 | int prev_index() const { |
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| 74 | return (tmppath[2*act]==last)? 2*act : 2*act+1; |
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| 75 | } |
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| 76 | |
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| 77 | int next() const { |
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| 78 | return tmppath[next_index()]; |
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| 79 | } |
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| 80 | |
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| 81 | int prev() const { |
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| 82 | return tmppath[prev_index()]; |
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| 83 | } |
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| 84 | |
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| 85 | It& operator++() { |
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| 86 | int tmp = act; |
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| 87 | act = next(); |
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| 88 | last = tmp; |
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| 89 | return *this; |
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| 90 | } |
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| 91 | |
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| 92 | operator int() const { |
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| 93 | return act; |
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| 94 | } |
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| 95 | |
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| 96 | private: |
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| 97 | const std::vector<int> &tmppath; |
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| 98 | int act; |
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| 99 | int last; |
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| 100 | }; |
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| 101 | |
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| 102 | bool check(std::vector<int> &path, It i, It j) { |
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| 103 | if (c(i, i.next()) + c(j, j.next()) > |
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| 104 | c(i, j) + c(j.next(), i.next())) { |
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| 105 | |
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| 106 | path[ It(path, i.next(), i).prev_index() ] = j.next(); |
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| 107 | path[ It(path, j.next(), j).prev_index() ] = i.next(); |
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| 108 | |
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| 109 | path[i.next_index()] = j; |
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| 110 | path[j.next_index()] = i; |
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| 111 | |
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| 112 | return true; |
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| 113 | } |
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| 114 | return false; |
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| 115 | } |
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| 116 | |
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| 117 | public: |
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| 118 | |
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| 119 | Cost run() { |
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| 120 | _path.clear(); |
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| 121 | |
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| 122 | if (_gr.nodeNum()>3) { |
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| 123 | |
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| 124 | opt2_tsp_label: |
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| 125 | It i(tmppath); |
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| 126 | It j(tmppath, i, i.prev()); |
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| 127 | ++j; ++j; |
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| 128 | for (; j.next()!=0; ++j) { |
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| 129 | if (check(tmppath, i, j)) |
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| 130 | goto opt2_tsp_label; |
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| 131 | } |
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| 132 | |
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| 133 | for (++i; i.next()!=0; ++i) { |
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| 134 | It j(tmppath, i, i.prev()); |
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| 135 | if (++j==0) |
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| 136 | break; |
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| 137 | if (++j==0) |
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| 138 | break; |
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| 139 | |
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| 140 | for (; j!=0; ++j) { |
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| 141 | if (check(tmppath, i, j)) |
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| 142 | goto opt2_tsp_label; |
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| 143 | } |
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| 144 | } |
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| 145 | } |
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| 146 | |
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| 147 | It k(tmppath); |
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| 148 | _path.push_back(_gr.nodeFromId(k)); |
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| 149 | for (++k; k!=0; ++k) |
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| 150 | _path.push_back(_gr.nodeFromId(k)); |
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| 151 | |
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| 152 | |
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| 153 | |
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| 154 | _sum = _cost[ _gr.edge(_path.back(), _path.front()) ]; |
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| 155 | for (unsigned int i=0; i<_path.size()-1; ++i) |
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| 156 | _sum += _cost[ _gr.edge(_path[i], _path[i+1]) ]; |
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| 157 | return _sum; |
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| 158 | } |
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| 159 | |
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| 160 | |
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| 161 | template <typename L> |
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| 162 | void tourNodes(L &container) { |
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| 163 | container(opt2_helper::vectorConvert<L>(_path)); |
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| 164 | } |
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| 165 | |
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| 166 | template <template <typename> class L> |
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| 167 | L<Node> tourNodes() { |
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| 168 | return opt2_helper::vectorConvert<L<Node> >(_path); |
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| 169 | } |
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| 170 | |
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| 171 | const std::vector<Node>& tourNodes() { |
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| 172 | return _path; |
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| 173 | } |
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| 174 | |
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| 175 | Path<FullGraph> tour() { |
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| 176 | Path<FullGraph> p; |
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| 177 | if (_path.size()<2) |
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| 178 | return p; |
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| 179 | |
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| 180 | for (unsigned int i=0; i<_path.size()-1; ++i) { |
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| 181 | p.addBack(_gr.arc(_path[i], _path[i+1])); |
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| 182 | } |
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| 183 | p.addBack(_gr.arc(_path.back(), _path.front())); |
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| 184 | return p; |
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| 185 | } |
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| 186 | |
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| 187 | Cost tourCost() { |
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| 188 | return _sum; |
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| 189 | } |
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| 190 | |
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| 191 | |
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| 192 | private: |
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| 193 | const FullGraph &_gr; |
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| 194 | const CostMap &_cost; |
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| 195 | Cost _sum; |
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| 196 | std::vector<int> tmppath; |
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| 197 | std::vector<Node> _path; |
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| 198 | }; |
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| 199 | |
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| 200 | |
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| 201 | }; // namespace lemon |
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| 202 | |
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| 203 | #endif |
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