1 | /* -*- C++ -*- |
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2 | * demo/dijkstra_demo.cc - Part of LEMON, a generic C++ optimization library |
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3 | * |
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4 | * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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5 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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6 | * |
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7 | * Permission to use, modify and distribute this software is granted |
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8 | * provided that this copyright notice appears in all copies. For |
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9 | * precise terms see the accompanying LICENSE file. |
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10 | * |
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11 | * This software is provided "AS IS" with no warranty of any kind, |
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12 | * express or implied, and with no claim as to its suitability for any |
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13 | * purpose. |
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14 | * |
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15 | */ |
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16 | |
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17 | ///\ingroup demos |
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18 | ///\file |
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19 | ///\brief Demonstrating LEMON implementation of the Dijkstra algorithm |
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20 | /// |
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21 | /// Dijkstra's algorithm computes shortest paths between two nodes in |
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22 | /// a graph with edge lengths. Here we only show some of the |
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23 | /// facilities supplied by our implementation: for the detailed |
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24 | /// documentation of the LEMON Dijkstra class read \ref lemon::Dijkstra "this". |
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25 | /// |
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26 | /// \include dijkstra_demo.cc |
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27 | |
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28 | #include <iostream> |
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29 | |
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30 | #include <lemon/list_graph.h> |
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31 | #include <lemon/dijkstra.h> |
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32 | |
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33 | using namespace lemon; |
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34 | |
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35 | |
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36 | int main (int, char*[]) |
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37 | { |
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38 | |
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39 | typedef ListGraph Graph; |
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40 | typedef Graph::Node Node; |
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41 | typedef Graph::Edge Edge; |
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42 | typedef Graph::EdgeMap<int> LengthMap; |
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43 | |
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44 | Graph g; |
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45 | |
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46 | //An example from Ahuja's book |
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47 | |
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48 | Node s=g.addNode(); |
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49 | Node v2=g.addNode(); |
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50 | Node v3=g.addNode(); |
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51 | Node v4=g.addNode(); |
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52 | Node v5=g.addNode(); |
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53 | Node t=g.addNode(); |
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54 | |
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55 | Edge s_v2=g.addEdge(s, v2); |
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56 | Edge s_v3=g.addEdge(s, v3); |
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57 | Edge v2_v4=g.addEdge(v2, v4); |
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58 | Edge v2_v5=g.addEdge(v2, v5); |
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59 | Edge v3_v5=g.addEdge(v3, v5); |
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60 | Edge v4_t=g.addEdge(v4, t); |
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61 | Edge v5_t=g.addEdge(v5, t); |
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62 | |
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63 | LengthMap len(g); |
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64 | |
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65 | len.set(s_v2, 10); |
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66 | len.set(s_v3, 10); |
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67 | len.set(v2_v4, 5); |
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68 | len.set(v2_v5, 8); |
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69 | len.set(v3_v5, 5); |
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70 | len.set(v4_t, 8); |
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71 | len.set(v5_t, 8); |
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72 | |
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73 | std::cout << "This program is a simple demo of the LEMON Dijkstra class." |
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74 | << std::endl; |
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75 | std::cout << |
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76 | "We calculate the shortest path from node s to node t in a graph." |
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77 | << std::endl; |
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78 | std::cout << std::endl; |
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79 | |
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80 | |
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81 | std::cout << "The id of s is " << g.id(s)<< ", the id of t is " |
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82 | << g.id(t) << "." << std::endl; |
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83 | |
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84 | std::cout << "Dijkstra algorithm demo..." << std::endl; |
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85 | |
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86 | Dijkstra<Graph, LengthMap> dijkstra_test(g,len); |
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87 | |
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88 | dijkstra_test.run(s); |
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89 | |
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90 | std::cout << "The distance of node t from node s: " |
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91 | << dijkstra_test.dist(t) << std::endl; |
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92 | |
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93 | std::cout << "The shortest path from s to t goes through the following " |
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94 | << "nodes (the first one is t, the last one is s): " |
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95 | << std::endl; |
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96 | |
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97 | for (Node v=t;v != s; v=dijkstra_test.predNode(v)) { |
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98 | std::cout << g.id(v) << "<-"; |
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99 | } |
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100 | |
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101 | std::cout << g.id(s) << std::endl; |
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102 | |
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103 | return 0; |
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104 | } |
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