使用 BFS 查找 Boost BGL 图中所有可到达的顶点

我构建了一个 boost BGL 图：

using vertex_t = std::variant<node_t, specialNode_t>; // structs
using edge_t = std::variant<TerminalType>;            // enum

using Graph_t = boost::adjacency_list<
    boost::vecS,
    boost::vecS,
    boost::undirectedS,
    vertex_t,
    edge_t>;

Graph_t myGraph;

我试图找到（收集）从某个起点（顶点）可到达的所有顶点（按距离排序）。这意味着我想创建一个从某个起始顶点可到达的所有顶点的列表，其中“较近”的顶点存储在列表/向量的前面。因此我（认为我）需要 BFS。

不幸的是我没能找到如何在没有编译错误的情况下做到这一点：

boost::queue<vertex_t> Q;
boost::default_bfs_visitor vis; // Will do my collecting visitor later...

auto indexmap = boost::get(boost::vertex_index, myGraph);
auto colormap = boost::make_vector_property_map<boost::default_color_type>(indexmap);

boost::breadth_first_visit(myGraph, start, std::ref(Q), vis, colormap);

这会导致以下错误：

Error   C2039   'push': is not a member of 'std::reference_wrapper<boost::queue<ListSim::vertex_t,std::deque<_Tp,std::allocator<_Ty>>>>'
Error   C2039   'empty': is not a member of 'std::reference_wrapper<boost::queue<ListSim::vertex_t,std::deque<_Tp,std::allocator<_Ty>>>>'
Error   C2039   'top': is not a member of 'std::reference_wrapper<boost::queue<ListSim::vertex_t,std::deque<_Tp,std::allocator<_Ty>>>>'
Error   C2039   'pop': is not a member of 'std::reference_wrapper<boost::queue<ListSim::vertex_t,std::deque<_Tp,std::allocator<_Ty>>>>'
Error   C2039   'push': is not a member of 'std::reference_wrapper<boost::queue<ListSim::vertex_t,std::deque<_Tp,std::allocator<_Ty>>>>'

我的问题：

1. 谁能阐明我的错误？或者也许是一个指向 例子？
2. 是否可能有更好的（在效率方面）或不同的方法来实现该目标？

（我想先使用“connected_components”......但它使用DFS，无法满足我的距离/排序标准）。

文档说缓冲区需要是一个队列vertex_descriptors。你不小心声明它有vertex_t（顶点属性包）作为值类型。

Fix it:

using vertex_descriptor = boost::graph_traits<Graph_t>::vertex_descriptor;

boost::queue<vertex_descriptor> Q;

它编译：

Live On Coliru https://coliru.stacked-crooked.com/a/25789d8ec9e5b68c

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/breadth_first_search.hpp>
#include <variant>

struct node_t {
};
struct specialNode_t {
};
enum class TerminalType {
};

using vertex_t = std::variant<node_t, specialNode_t>; // structs
using edge_t = std::variant<TerminalType>;            // enum

using Graph_t = boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, vertex_t, edge_t>;

int main() {
    Graph_t myGraph(5);
    boost::default_bfs_visitor vis; // Will do my collecting visitor later...

    auto indexmap = boost::get(boost::vertex_index, myGraph);
    auto colormap = boost::make_vector_property_map<boost::default_color_type>(indexmap);

    using vertex_descriptor = boost::graph_traits<Graph_t>::vertex_descriptor;

    boost::queue<vertex_descriptor> Q;
    boost::breadth_first_visit(myGraph, 0, Q, vis, colormap);
}