提升图形库 - 深度优先 仅通过连接的顶点进行搜索

Boost Graph Library - Depth First Search only through connected vertices

本文关键字：连接 顶点 搜索 图形库 深度优先      更新时间：2023-10-16

我正在尝试通过具有多个不相交图的图形运行DFS。我想指定起始顶点，并让 DFS 仅遍历该树，保留在向量中访问的顶点 ID。为此，我需要depth_first_visit函数 http://www.boost.org/doc/libs/1_55_0/libs/graph/doc/depth_first_visit.html

该函数要求我初始化颜色图，而我对此一无所知，因为我还有一个自定义顶点和一个自定义边。我得到的最好的例子是这篇文章和这篇文章，它谈论的是深度优先搜索而不是深度首次访问。如果我用我使用的结构替换顶点，那么它将是下面的代码。

因此，重申一下，我对如何初始化颜色图并为自定义顶点类型设置起始顶点一无所知。我希望有人能给我一个简单的例子。过去几个小时一直在谷歌搜索，但找不到一个例子。

// Boost DFS example on an undirected graph.
// Create a sample graph, traverse its nodes
// in DFS order and print out their values.
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/depth_first_search.hpp>
#include <iostream>
using namespace std;
//======================================================================================================
//information representing each vertex
struct Vertex {
public:
//id
int id = 0;
int parent_id = -1;
int l_child = -1, r_child = -1;
Vertex(int id = -1) : id(id) {}
};
//======================================================================================================
//information representing each weight
//it carries the boundary length and also the distance
struct Edge {
//distance
float boundary_length = 0;
float weight = 1;
//float L, a, b = 1;
Edge(float boundary_length = 1) : boundary_length(boundary_length) {}
};
typedef boost::adjacency_list<boost::listS, boost::vecS, boost::undirectedS, Vertex, Edge> Graph;
class MyVisitor : public boost::default_dfs_visitor
{
public:
MyVisitor() : vv(new std::vector<int>()) {}
void discover_vertex(int v, const Graph& g) const
{
vv->push_back(g[v].id);
return;
}
std::vector<int>& GetVector() const { return *vv; }
private:
boost::shared_ptr< std::vector<int> > vv;
};
int main()
{
Graph g;
boost::add_edge(0, 1, g);
boost::add_edge(0, 2, g);
boost::add_edge(1, 2, g);
boost::add_edge(1, 3, g);
boost::add_edge(5, 6, g);
boost::add_edge(5, 8, g);
MyVisitor vis;
boost::depth_first_search(g, boost::visitor(vis));
std::vector<int> vctr = vis.GetVector();
return 0;
}

最简单的方法是创建一个矢量来包含每个顶点的颜色。

实现这一目标的最简单方法是：

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

然后你像

boost::depth_first_search(g, vis, colormap);

这相当于使用命名参数习惯用法，如下所示：

boost::depth_first_search(g, boost::visitor(vis) .color_map(colormap));

要同时提供起始顶点，只需使用该重载：

boost::depth_first_search(g, vis, colormap, 1);

住在科里鲁

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/depth_first_search.hpp>
#include <iostream>
using namespace std;
//======================================================================================================
// information representing each vertex
struct Vertex {
int id = 0;
int parent_id = -1;
int l_child = -1, r_child = -1;
Vertex(int id = -1) : id(id) {}
};
//======================================================================================================
// information representing each weight
// it carries the boundary length and also the distance
struct Edge {
// distance
float boundary_length = 0;
float weight = 1;
// float L, a, b = 1;
Edge(float boundary_length = 1) : boundary_length(boundary_length) {}
};
typedef boost::adjacency_list<boost::listS, boost::vecS, boost::undirectedS, Vertex, Edge> Graph;
class MyVisitor : public boost::default_dfs_visitor {
public:
MyVisitor() : vv(new std::vector<int>()) {}
void discover_vertex(int v, const Graph &g) const {
vv->push_back(g[v].id);
return;
}
std::vector<int> &GetVector() const { return *vv; }
private:
boost::shared_ptr<std::vector<int> > vv;
};
int main() {
Graph g;
boost::add_edge(0, 1, g);
boost::add_edge(0, 2, g);
boost::add_edge(1, 2, g);
boost::add_edge(1, 3, g);
boost::add_edge(5, 6, g);
boost::add_edge(5, 8, g);
for (auto v : boost::make_iterator_range(boost::vertices(g)))
g[v] = Vertex(v);
auto indexmap = boost::get(boost::vertex_index, g);
auto colormap = boost::make_vector_property_map<boost::default_color_type>(indexmap);
MyVisitor vis;
boost::depth_first_search(g, vis, colormap, 1);
std::vector<int> vctr = vis.GetVector();
for(auto id : vctr)
std::cout << id << " ";
}

指纹

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