C++ Boost graph 深度（广度）优先算法示例

//整理 by RobinKin from DevonIT.inc
#include <boost/config.hpp>
#include <iostream>
#include <vector>
#include <string>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/depth_first_search.hpp>
#include <boost/graph/breadth_first_search.hpp>
#include <boost/property_map.hpp>
#include <boost/graph/graph_utility.hpp> // for boost::make_list

/*
Example of using a visitor with the depth first search
and breadth first search algorithm

Sacramento ---- Reno ---- Salt Lake City
|
San Francisco
|
San Jose ---- Fresno
|
Los Angeles ---- Los Vegas ---- Pheonix
|
San Diego

The visitor has three main functions:

discover_vertex(u,g) is invoked when the algorithm first arrives at the
vertex u. This will happen in the depth first or breadth first
order depending on which algorithm you use.

examine_edge(e,g) is invoked when the algorithm first checks an edge to see
whether it has already been there. Whether using BFS or DFS, all
the edges of vertex u are examined immediately after the call to
visit(u).

finish_vertex(u,g) is called when after all the vertices reachable from vertex
u have already been visited.

*/

using namespace std;
using namespace boost;

//到达结点时 operator()

struct city_arrival : public base_visitor<city_arrival>
{
city_arrival(string* n) : names(n) { }
typedef on_discover_vertex event_filter;
template <class Vertex, class Graph>
inline void operator()(Vertex u, Graph&) {
cout << endl << "arriving at " << names[u] << endl
<< " neighboring cities are: ";
}
string* names;
};

//显示邻接结点时 。调用 operator()
struct neighbor_cities : public base_visitor<neighbor_cities>
{
neighbor_cities(string* n) : names(n) { }
typedef on_examine_edge event_filter;
template <class Edge, class Graph>
inline void operator()(Edge e, Graph& g) {
cout << names[ target(e, g) ] << ", ";
}
string* names;
};

//某结点的所有邻接结点都已经被访问过时 调用 operator()

struct finish_city : public base_visitor<finish_city>
{
finish_city(string* n) : names(n) { }
typedef on_finish_vertex event_filter;
template <class Vertex, class Graph>
inline void operator()(Vertex u, Graph&) {
cout << endl << "finished with " << names[u] << endl;
}
string* names;
};

int main(int, char*[])
{

enum { SanJose, SanFran, LA, SanDiego, Fresno, LosVegas, Reno,
Sacramento, SaltLake, Pheonix, N };

string names[] = { "San Jose", "San Francisco", "San Jose",
"San Francisco", "Los Angeles", "San Diego",
"Fresno", "Los Vegas", "Reno", "Sacramento",
"Salt Lake City", "Pheonix" };

typedef std::pair<int,int> E;
E edge_array[] = { E(Sacramento, Reno), E(Sacramento, SanFran),
E(Reno, SaltLake),
E(SanFran, SanJose),
E(SanJose, Fresno), E(SanJose, LA),
E(LA, LosVegas), E(LA, SanDiego),
E(LosVegas, Pheonix) };

/* Create the graph type we want. */
typedef adjacency_list<vecS, vecS, undirectedS> Graph;

Graph G(edge_array, edge_array + sizeof(edge_array)/sizeof(E), N);

cout << "*** Depth First ***" << endl;

//第 1 2 3 个参数分别是 arrival neighbor finish
depth_first_search
(G,
visitor(make_dfs_visitor(boost::make_list(city_arrival(names),
neighbor_cities(names),
finish_city(names)))));
cout << endl;

/* Get the source vertex */
boost::graph_traits<Graph>::vertex_descriptor
s = vertex(SanJose,G);

cout << "*** Breadth First ***" << endl;
breadth_first_search
(G, s, visitor(make_bfs_visitor(boost::make_list(city_arrival(names),
neighbor_cities(names),
finish_city(names)))));

return 0;
}

//输出：
*** Depth First ***

arriving at San Jose
neighboring cities are: San Francisco,
arriving at San Francisco
neighboring cities are: Los Vegas,
arriving at Los Vegas
neighboring cities are: Fresno,
arriving at Fresno
neighboring cities are: Los Vegas, Reno,
arriving at Reno
neighboring cities are: Fresno,
finished with Reno

finished with Fresno
San Francisco,
finished with Los Vegas
San Jose,
finished with San Francisco
Los Angeles,
arriving at Los Angeles
neighboring cities are: San Jose,
finished with Los Angeles