/* -*- 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;

}