64 lines
2.2 KiB
C++
64 lines
2.2 KiB
C++
//=======================================================================
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// Copyright 2001 Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee,
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//=======================================================================
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#include <iostream>
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#include <boost/graph/edge_list.hpp>
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#include <boost/graph/bellman_ford_shortest_paths.hpp>
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int
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main()
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{
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using namespace boost;
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// ID numbers for the routers (vertices).
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enum
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{ A, B, C, D, E, F, G, H, n_vertices };
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const int n_edges = 11;
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typedef std::pair < int, int >Edge;
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// The list of connections between routers stored in an array.
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Edge edges[] = {
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Edge(A, B), Edge(A, C),
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Edge(B, D), Edge(B, E), Edge(C, E), Edge(C, F), Edge(D, H),
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Edge(D, E), Edge(E, H), Edge(F, G), Edge(G, H)
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};
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// Specify the graph type and declare a graph object
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typedef edge_list < Edge*, Edge, std::ptrdiff_t, std::random_access_iterator_tag> Graph;
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Graph g(edges, edges + n_edges);
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// The transmission delay values for each edge.
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float delay[] =
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{5.0, 1.0, 1.3, 3.0, 10.0, 2.0, 6.3, 0.4, 1.3, 1.2, 0.5};
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// Declare some storage for some "external" vertex properties.
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char name[] = "ABCDEFGH";
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int parent[n_vertices];
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for (int i = 0; i < n_vertices; ++i)
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parent[i] = i;
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float distance[n_vertices];
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std::fill(distance, distance + n_vertices, (std::numeric_limits < float >::max)());
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// Specify A as the source vertex
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distance[A] = 0;
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bool r = bellman_ford_shortest_paths(g, int (n_vertices),
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weight_map(make_iterator_property_map
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(&delay[0],
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get(edge_index, g),
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delay[0])).
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distance_map(&distance[0]).
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predecessor_map(&parent[0]));
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if (r)
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for (int i = 0; i < n_vertices; ++i)
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std::cout << name[i] << ": " << distance[i]
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<< " " << name[parent[i]] << std::endl;
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else
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std::cout << "negative cycle" << std::endl;
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return EXIT_SUCCESS;
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}
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