Boost C++ Libraries

libs/graph/example/boykov_kolmogorov-eg.cpp

//  Copyright (c) 2006, Stephan Diederich
//
//  This code may be used under either of the following two licences:
//
//    Permission is hereby granted, free of charge, to any person
//    obtaining a copy of this software and associated documentation
//    files (the "Software"), to deal in the Software without
//    restriction, including without limitation the rights to use,
//    copy, modify, merge, publish, distribute, sublicense, and/or
//    sell copies of the Software, and to permit persons to whom the
//    Software is furnished to do so, subject to the following
//    conditions:
//
//    The above copyright notice and this permission notice shall be
//    included in all copies or substantial portions of the Software.
//
//    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
//    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
//    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
//    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
//    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
//    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
//    OTHER DEALINGS IN THE SOFTWARE. OF SUCH DAMAGE.
//
//  Or:
//
//    Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE_1_0.txt or copy at
//    http://www.boost.org/LICENSE_1_0.txt)

#include <boost/config.hpp>
#include <iostream>
#include <string>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/boykov_kolmogorov_max_flow.hpp>
#include <boost/graph/read_dimacs.hpp>
#include <boost/graph/graph_utility.hpp>

// Use a DIMACS network flow file as stdin.
// boykov_kolmogorov-eg < max_flow.dat
//
// Sample output:
// c  The total flow:
// s 13
//
// c flow values:
// f 0 6 3
// f 0 1 6
// f 0 2 4
// f 1 5 1
// f 1 0 0
// f 1 3 5
// f 2 4 4
// f 2 3 0
// f 2 0 0
// f 3 7 5
// f 3 2 0
// f 3 1 0
// f 4 5 0
// f 4 6 4
// f 5 4 0
// f 5 7 1
// f 6 7 7
// f 6 4 0
// f 7 6 0
// f 7 5 0

int main()
{
    using namespace boost;

    typedef adjacency_list_traits< vecS, vecS, directedS > Traits;
    typedef adjacency_list< vecS, vecS, directedS,
        property< vertex_name_t, std::string,
            property< vertex_index_t, long,
                property< vertex_color_t, boost::default_color_type,
                    property< vertex_distance_t, long,
                        property< vertex_predecessor_t,
                            Traits::edge_descriptor > > > > >,

        property< edge_capacity_t, long,
            property< edge_residual_capacity_t, long,
                property< edge_reverse_t, Traits::edge_descriptor > > > >
        Graph;

    Graph g;
    property_map< Graph, edge_capacity_t >::type capacity
        = get(edge_capacity, g);
    property_map< Graph, edge_residual_capacity_t >::type residual_capacity
        = get(edge_residual_capacity, g);
    property_map< Graph, edge_reverse_t >::type rev = get(edge_reverse, g);
    Traits::vertex_descriptor s, t;
    read_dimacs_max_flow(g, capacity, rev, s, t);

    std::vector< default_color_type > color(num_vertices(g));
    std::vector< long > distance(num_vertices(g));
    long flow = boykov_kolmogorov_max_flow(g, s, t);

    std::cout << "c  The total flow:" << std::endl;
    std::cout << "s " << flow << std::endl << std::endl;

    std::cout << "c flow values:" << std::endl;
    graph_traits< Graph >::vertex_iterator u_iter, u_end;
    graph_traits< Graph >::out_edge_iterator ei, e_end;
    for (boost::tie(u_iter, u_end) = vertices(g); u_iter != u_end; ++u_iter)
        for (boost::tie(ei, e_end) = out_edges(*u_iter, g); ei != e_end; ++ei)
            if (capacity[*ei] > 0)
                std::cout << "f " << *u_iter << " " << target(*ei, g) << " "
                          << (capacity[*ei] - residual_capacity[*ei])
                          << std::endl;

    return EXIT_SUCCESS;
}