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boost库中最短单源路径算法,主要是 dijkstra_shortest_paths函数。
输入数据:
- {
- "start": "A",
- "end": "D",
- "edge_list": [
- ["A", "C"],
- ["B", "B"],
- ["B", "D"],
- ["B", "E"],
- ["C", "B"],
- ["C", "D"],
- ["D", "E"],
- ["E", "A"],
- ["E", "B"]
- ],
- "weight_list": [
- 1, 2, 1, 2, 7, 3, 1, 1, 1
- ]
- }
其中 start是 起点A,end是终点D, 然后 到各个点的权重是 weight_list.
输出为: 其中 path是 A->D的最短路径和权重, parent是 对应的父路径和权重。
- {
- "parent": [
- [ "A", "A", 0.0 ],
- [ "B", "E", 6.0 ],
- [ "C", "A", 1.0 ],
- [ "D", "C", 4.0 ],
- [ "E", "D", 5.0 ]
- ],
- "path": [
- [ "A", 0.0 ],
- [ "C", 1.0 ],
- [ "D", 3.0 ]
- ]
- }
可视化算法为:
boost库代码的demo如下:
- #include <boost/config.hpp>
- #include <iostream>
- #include <fstream>
-
- #include <boost/graph/graph_traits.hpp>
- #include <boost/graph/adjacency_list.hpp>
- #include <boost/graph/dijkstra_shortest_paths.hpp>
-
- using namespace boost;
-
- int main(int, char*[])
- {
- typedef adjacency_list_traits< listS, listS, directedS >::vertex_descriptor
- vertex_descriptor;
- typedef adjacency_list< listS, listS, directedS,
- property< vertex_index_t, int,
- property< vertex_name_t, char,
- property< vertex_distance_t, int,
- property< vertex_predecessor_t, vertex_descriptor > > > >,
- property< edge_weight_t, int > >
- graph_t;
- typedef std::pair< int, int > Edge;
-
- const int num_nodes = 5;
- enum nodes
- {
- A,
- B,
- C,
- D,
- E
- };
- Edge edge_array[] = { Edge(A, C), Edge(B, B), Edge(B, D), Edge(B, E),
- Edge(C, B), Edge(C, D), Edge(D, E), Edge(E, A), Edge(E, B) };
- int weights[] = { 1, 2, 1, 2, 7, 3, 1, 1, 1 };
- int num_arcs = sizeof(edge_array) / sizeof(Edge);
- graph_traits< graph_t >::vertex_iterator i, iend;
-
- graph_t g(edge_array, edge_array + num_arcs, weights, num_nodes);
- property_map< graph_t, edge_weight_t >::type weightmap
- = get(edge_weight, g);
-
- // Manually intialize the vertex index and name maps
- property_map< graph_t, vertex_index_t >::type indexmap
- = get(vertex_index, g);
- property_map< graph_t, vertex_name_t >::type name = get(vertex_name, g);
- int c = 0;
- for (boost::tie(i, iend) = vertices(g); i != iend; ++i, ++c)
- {
- indexmap[*i] = c;
- name[*i] = 'A' + c;
- }
-
- vertex_descriptor s = vertex(A, g);
-
- property_map< graph_t, vertex_distance_t >::type d
- = get(vertex_distance, g);
- property_map< graph_t, vertex_predecessor_t >::type p
- = get(vertex_predecessor, g);
- dijkstra_shortest_paths(g, s, predecessor_map(p).distance_map(d));
-
- std::cout << "distances and parents:" << std::endl;
- graph_traits< graph_t >::vertex_iterator vi, vend;
- for (boost::tie(vi, vend) = vertices(g); vi != vend; ++vi)
- {
- std::cout << "distance(" << name[*vi] << ") = " << d[*vi] << ", ";
- std::cout << "parent(" << name[*vi] << ") = " << name[p[*vi]]
- << std::endl;
- }
- std::cout << std::endl;
-
- return EXIT_SUCCESS;
- }
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