zsuzska@1578: /* -*- C++ -*-
zsuzska@1578:  * demo/kruskal_demo.cc - Part of LEMON, a generic C++ optimization library
zsuzska@1578:  *
zsuzska@1578:  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
zsuzska@1578:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
zsuzska@1578:  *
zsuzska@1578:  * Permission to use, modify and distribute this software is granted
zsuzska@1578:  * provided that this copyright notice appears in all copies. For
zsuzska@1578:  * precise terms see the accompanying LICENSE file.
zsuzska@1578:  *
zsuzska@1578:  * This software is provided "AS IS" with no warranty of any kind,
zsuzska@1578:  * express or implied, and with no claim as to its suitability for any
zsuzska@1578:  * purpose.
zsuzska@1578:  *
zsuzska@1578:  */
zsuzska@1578: 
zsuzska@1578: ///\ingroup demos
zsuzska@1578: ///\file
zsuzska@1578: ///\brief Minimum weight spanning tree by Kruskal algorithm (demo).
zsuzska@1578: ///
zsuzska@1578: ///This demo program shows how to find a minimum weight spannin tree
zsuzska@1578: ///of a graph by using the Kruskal algorithm. 
zsuzska@1578: 
athos@1182: #include <iostream>
athos@1182: #include <vector>
athos@1182: 
athos@1182: #include <lemon/maps.h>
athos@1182: #include <lemon/kruskal.h>
athos@1182: #include <lemon/list_graph.h>
athos@1182: 
athos@1182: 
athos@1182: using namespace std;
athos@1182: using namespace lemon;
athos@1182: 
athos@1182: 
athos@1182: int main() {
athos@1182: 
athos@1182:   typedef ListGraph::Node Node;
athos@1182:   typedef ListGraph::Edge Edge;
athos@1182:   typedef ListGraph::NodeIt NodeIt;
athos@1182:   typedef ListGraph::EdgeIt EdgeIt;
athos@1182: 
zsuzska@1578:   ListGraph g;
zsuzska@1578:   //Make an example graph g.
zsuzska@1578:   Node s=g.addNode();
zsuzska@1578:   Node v1=g.addNode();
zsuzska@1578:   Node v2=g.addNode();
zsuzska@1578:   Node v3=g.addNode();
zsuzska@1578:   Node v4=g.addNode();
zsuzska@1578:   Node t=g.addNode();
zsuzska@1578:   
zsuzska@1578:   Edge e1 = g.addEdge(s, v1);
zsuzska@1578:   Edge e2 = g.addEdge(s, v2);
zsuzska@1578:   Edge e3 = g.addEdge(v1, v2);
zsuzska@1578:   Edge e4 = g.addEdge(v2, v1);
zsuzska@1578:   Edge e5 = g.addEdge(v1, v3);
zsuzska@1578:   Edge e6 = g.addEdge(v3, v2);
zsuzska@1578:   Edge e7 = g.addEdge(v2, v4);
zsuzska@1578:   Edge e8 = g.addEdge(v4, v3);
zsuzska@1578:   Edge e9 = g.addEdge(v3, t);
zsuzska@1578:   Edge e10 = g.addEdge(v4, t);
athos@1182: 
zsuzska@1578:   //Make the input and output for the kruskal.
athos@1182:   typedef ListGraph::EdgeMap<int> ECostMap;
athos@1182:   typedef ListGraph::EdgeMap<bool> EBoolMap;
athos@1182: 
zsuzska@1578:   ECostMap edge_cost_map(g, 2);
zsuzska@1578:   EBoolMap tree_map(g);
athos@1182: 
zsuzska@1578:   // Kruskal.
zsuzska@1578:   std::cout << "The weight of the minimum spanning tree by using Kruskal algorithm is " 
zsuzska@1578: 	    << kruskal(g, ConstMap<ListGraph::Edge,int>(2), tree_map)<<std::endl;
athos@1182: 
zsuzska@1578:   //Make another input (non-uniform costs) for the kruskal.
zsuzska@1578:   ECostMap edge_cost_map_2(g);
zsuzska@1578:   edge_cost_map_2.set(e1, -10);
zsuzska@1578:   edge_cost_map_2.set(e2, -9);
zsuzska@1578:   edge_cost_map_2.set(e3, -8);
zsuzska@1578:   edge_cost_map_2.set(e4, -7);
zsuzska@1578:   edge_cost_map_2.set(e5, -6);
zsuzska@1578:   edge_cost_map_2.set(e6, -5);
zsuzska@1578:   edge_cost_map_2.set(e7, -4);
zsuzska@1578:   edge_cost_map_2.set(e8, -3);
zsuzska@1578:   edge_cost_map_2.set(e9, -2);
zsuzska@1578:   edge_cost_map_2.set(e10, -1);
athos@1182: 
athos@1182:   vector<Edge> tree_edge_vec;
athos@1182: 
zsuzska@1578:   //Test with non uniform costs and inserter.
zsuzska@1578:   std::cout << "The weight of the minimum spanning tree with non-uniform costs is " << 
zsuzska@1578:     kruskal(g, edge_cost_map_2, std::back_inserter(tree_edge_vec)) <<std::endl;
athos@1182: 
zsuzska@1578:   //The vector for the edges of the output tree.
athos@1182:   tree_edge_vec.clear();
athos@1182: 
zsuzska@1578:   //Test with makeKruskalSequenceOutput and makeKruskalSequenceOutput.
athos@1182: 
zsuzska@1578:   std::cout << "The weight of the minimum spanning tree again is " << 
zsuzska@1578:    kruskal(g,makeKruskalMapInput(g,edge_cost_map_2),makeKruskalSequenceOutput(std::back_inserter(tree_edge_vec)))<< std::endl;
athos@1182: 
zsuzska@1578: 
athos@1182:   return 0;
athos@1182: }