/* -*- C++ -*-

  * demo/kruskal_demo.cc - Part of LEMON, a generic C++ optimization library

  *

  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Research Group on Combinatorial Optimization, EGRES).

  *

  * Permission to use, modify and distribute this software is granted

  * provided that this copyright notice appears in all copies. For

  * precise terms see the accompanying LICENSE file.

  *

  * This software is provided "AS IS" with no warranty of any kind,

  * express or implied, and with no claim as to its suitability for any

  * purpose.

  *

  */

 ///\ingroup demos

 ///\file

 ///\brief Minimum weight spanning tree by Kruskal algorithm (demo).

 ///

 ///This demo program shows how to find a minimum weight spannin tree

 ///of a graph by using the Kruskal algorithm. 

 #include <iostream>

 #include <vector>

 #include <lemon/maps.h>

 #include <lemon/kruskal.h>

 #include <lemon/list_graph.h>

 using namespace std;

 using namespace lemon;

 int main() {

   typedef ListGraph::Node Node;

   typedef ListGraph::Edge Edge;

   typedef ListGraph::NodeIt NodeIt;

   typedef ListGraph::EdgeIt EdgeIt;

   ListGraph g;

   //Make an example graph g.

   Node s=g.addNode();

   Node v1=g.addNode();

   Node v2=g.addNode();

   Node v3=g.addNode();

   Node v4=g.addNode();

   Node t=g.addNode();

   Edge e1 = g.addEdge(s, v1);

   Edge e2 = g.addEdge(s, v2);

   Edge e3 = g.addEdge(v1, v2);

   Edge e4 = g.addEdge(v2, v1);

   Edge e5 = g.addEdge(v1, v3);

   Edge e6 = g.addEdge(v3, v2);

   Edge e7 = g.addEdge(v2, v4);

   Edge e8 = g.addEdge(v4, v3);

   Edge e9 = g.addEdge(v3, t);

   Edge e10 = g.addEdge(v4, t);

   //Make the input and output for the kruskal.

   typedef ListGraph::EdgeMap<int> ECostMap;

   typedef ListGraph::EdgeMap<bool> EBoolMap;

   ECostMap edge_cost_map(g, 2);

   EBoolMap tree_map(g);

   // Kruskal.

   std::cout << "The weight of the minimum spanning tree by using Kruskal algorithm is " 

 	    << kruskal(g, ConstMap<ListGraph::Edge,int>(2), tree_map)<<std::endl;

   //Make another input (non-uniform costs) for the kruskal.

   ECostMap edge_cost_map_2(g);

   edge_cost_map_2.set(e1, -10);

   edge_cost_map_2.set(e2, -9);

   edge_cost_map_2.set(e3, -8);

   edge_cost_map_2.set(e4, -7);

   edge_cost_map_2.set(e5, -6);

   edge_cost_map_2.set(e6, -5);

   edge_cost_map_2.set(e7, -4);

   edge_cost_map_2.set(e8, -3);

   edge_cost_map_2.set(e9, -2);

   edge_cost_map_2.set(e10, -1);

   vector<Edge> tree_edge_vec;

   //Test with non uniform costs and inserter.

   std::cout << "The weight of the minimum spanning tree with non-uniform costs is " << 

     kruskal(g, edge_cost_map_2, std::back_inserter(tree_edge_vec)) <<std::endl;

   //The vector for the edges of the output tree.

   tree_edge_vec.clear();

   //Test with makeKruskalMapInput and makeKruskalSequenceOutput.

   std::cout << "The weight of the minimum spanning tree again is " << 

    kruskal(g,makeKruskalMapInput(g,edge_cost_map_2),makeKruskalSequenceOutput(std::back_inserter(tree_edge_vec)))<< std::endl;

   return 0;

 }