graph/example/max_flow.cpp

100 lines
2.7 KiB
C++

//=======================================================================
// Copyright 2000 University of Notre Dame.
// Authors: Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee
//
// 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)
//=======================================================================
#ifdef _MSC_VER
#define _CRT_SECURE_NO_WARNINGS
#endif
#include <boost/config.hpp>
#include <iostream>
#include <string>
#include <boost/graph/push_relabel_max_flow.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/read_dimacs.hpp>
#include <boost/graph/graph_utility.hpp>
// Use a DIMACS network flow file as stdin.
// max_flow < 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 4
// f 4 6 0
// f 5 4 0
// f 5 7 5
// f 6 7 3
// 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<listS, vecS, directedS,
property<vertex_name_t, std::string>,
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_reverse_t>::type
rev = get(edge_reverse, g);
property_map<Graph, edge_residual_capacity_t>::type
residual_capacity = get(edge_residual_capacity, g);
Traits::vertex_descriptor s, t;
read_dimacs_max_flow(g, capacity, rev, s, t);
long flow;
#if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
// Use non-named parameter version
property_map<Graph, vertex_index_t>::type
indexmap = get(vertex_index, g);
flow = push_relabel_max_flow(g, s, t, capacity, residual_capacity, rev, indexmap);
#else
flow = push_relabel_max_flow(g, s, t);
#endif
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 0;
}