1 | // -*- c++ -*- |
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2 | #include <vector> |
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3 | #include <cstdlib> |
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4 | |
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5 | namespace hugo { |
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6 | |
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7 | |
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8 | /** |
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9 | * Inicializalja a veletlenszamgeneratort. |
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10 | * Figyelem, ez nem jo igazi random szamokhoz, |
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11 | * erre ne bizzad a titkaidat! |
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12 | */ |
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13 | void random_init() |
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14 | { |
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15 | unsigned int seed = getpid(); |
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16 | seed |= seed << 15; |
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17 | seed ^= time(0); |
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18 | |
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19 | srand(seed); |
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20 | } |
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21 | |
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22 | |
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23 | /** |
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24 | * Egy veletlen int-et ad vissza 0 es m-1 kozott. |
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25 | */ |
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26 | int random(int m) |
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27 | { |
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28 | return int( double(m) * rand() / (RAND_MAX + 1.0) ); |
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29 | } |
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30 | |
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31 | |
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32 | /// Generates a random graph with n nodes and m edges. |
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33 | /// Before generating the random graph, \c g.clear() is called. |
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34 | template<typename Graph> |
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35 | void randomGraph(Graph& g, int n, int m) { |
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36 | g.clear(); |
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37 | std::vector<typename Graph::Node> nodes; |
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38 | for (int i=0; i<n; ++i) |
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39 | nodes.push_back(g.addNode()); |
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40 | for (int i=0; i<m; ++i) |
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41 | g.addEdge(nodes[random(n)], nodes[random(n)]); |
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42 | } |
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43 | |
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44 | /// Generates a random bipartite graph with a and b nodes |
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45 | /// in the color classes and m edges. |
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46 | /// According to the bipartite graph concept, the resulting |
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47 | /// graph is directed from the first class to the second one. |
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48 | /// Before generating the random graph, \c g.clear() is called. |
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49 | template<typename Graph> |
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50 | void randomBipartiteGraph(Graph& g, int a, int b, int m) { |
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51 | g.clear(); |
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52 | std::vector<typename Graph::Node> s_nodes; |
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53 | std::vector<typename Graph::Node> t_nodes; |
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54 | for (int i=0; i<a; ++i) |
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55 | ///\bug g.addNode(g.S_CLASS) would be better. |
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56 | s_nodes.push_back(g.addNode(false)); |
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57 | for (int i=0; i<b; ++i) |
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58 | ///\bug g.addNode(g.T_CLASS) would be better. |
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59 | t_nodes.push_back(g.addNode(true)); |
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60 | for (int i=0; i<m; ++i) |
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61 | g.addEdge(s_nodes[random(a)], t_nodes[random(b)]); |
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62 | } |
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63 | |
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64 | /// Generates a complete graph in the undirected sense |
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65 | /// with n nodes and m edges. |
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66 | /// Before generating the random graph, \c g.clear() is called. |
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67 | template<typename Graph> |
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68 | void completeGraph(Graph& g, int n) { |
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69 | g.clear(); |
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70 | std::vector<typename Graph::Node> nodes; |
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71 | for (int i=0; i<n; ++i) |
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72 | nodes.push_back(g.addNode()); |
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73 | for (int i=0; i<n; ++i) |
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74 | for (int j=i+1; j<n; ++j) |
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75 | g.addEdge(nodes[i], nodes[j]); |
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76 | } |
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77 | |
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78 | } //namespace hugo |
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