/* -*- C++ -*-

 * src/test/max_matching_test.cc - Part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Combinatorial Optimization Research Group, 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.

 *

 */

#include <iostream>

#include <queue>

#include <math.h>

#include <cstdlib>

#include "test_tools.h"

#include <lemon/invalid.h>

#include <lemon/list_graph.h>

#include <graph_gen.h>

#include <max_matching.h>

using namespace std;

using namespace lemon;

int main() {

  typedef UndirListGraph Graph;

  typedef Graph::Edge Edge;

  typedef Graph::UndirEdgeIt UndirEdgeIt;

  typedef Graph::IncEdgeIt IncEdgeIt;

  typedef Graph::NodeIt NodeIt;

  typedef Graph::Node Node;

  Graph G;

  random_init(); 

  randomGraph(G, random(5000), random(20000) );  

  MaxMatching<Graph> max_matching(G);

  max_matching.runEdmonds(0);

  int s=0;

  Graph::NodeMap<Node> mate(G,INVALID);

  max_matching.writeNMapNode(mate);

  for(NodeIt v(G); v!=INVALID; ++v) {

    if ( mate[v]!=INVALID ) ++s;

  }

  int size=(int)s/2;  //size will be used as the size of a maxmatching

  check ( size == max_matching.size(), "mate() returns a different size matching than max_matching.size()" );

  Graph::NodeMap<MaxMatching<Graph>::pos_enum> pos0(G);

  max_matching.writePos(pos0);

  max_matching.resetPos();

  max_matching.resetMatching();

  max_matching.runEdmonds(1);

  s=0;

  max_matching.writeNMapNode(mate);

  for(NodeIt v(G); v!=INVALID; ++v) {

    if ( mate[v]!=INVALID ) ++s;

  }

  check ( (int)s/2 == size, "The size does not equal!" );

  Graph::NodeMap<MaxMatching<Graph>::pos_enum> pos1(G);

  max_matching.writePos(pos1);

  max_matching.resetPos();

  max_matching.run();

  s=0;

  max_matching.writeNMapNode(mate);

  for(NodeIt v(G); v!=INVALID; ++v) {

    if ( mate[v]!=INVALID ) ++s;

  }

  check ( (int)s/2 == size, "The size does not equal!" ); 

  Graph::NodeMap<MaxMatching<Graph>::pos_enum> pos2(G);

  max_matching.writePos(pos2);

  max_matching.resetPos();

  max_matching.resetMatching();

  max_matching.run();

  s=0;

  max_matching.writeNMapNode(mate);

  for(NodeIt v(G); v!=INVALID; ++v) {

    if ( mate[v]!=INVALID ) ++s;

  }

  check ( (int)s/2 == size, "The size does not equal!" ); 

  Graph::NodeMap<MaxMatching<Graph>::pos_enum> pos(G);

  max_matching.writePos(pos);

  bool ismatching=true;

  for(NodeIt v(G); v!=INVALID; ++v) {

    if ( mate[v]!=INVALID ) {

      Node u=mate[v];

      if (mate[u]!=v) ismatching=false; 

    }

  }  

  check ( ismatching, "It is not a matching!" );

  bool coincide=true;

  for(NodeIt v(G); v!=INVALID; ++v) {

   if ( pos0[v] != pos1[v] || pos1[v]!=pos2[v] || pos2[v]!=pos[v] ) {

     coincide=false;

    }

  }

  check ( coincide, "The decompositions do not coincide! " );

  bool noedge=true;

  for(UndirEdgeIt e(G); e!=INVALID; ++e) {

   if ( (pos[G.target(e)]==max_matching.C && pos[G.source(e)]==max_matching.D) || 

	 (pos[G.target(e)]==max_matching.D && pos[G.source(e)]==max_matching.C) )

      noedge=false; 

  }

  check ( noedge, "There are edges between D and C!" );

  bool oddcomp=true;

  Graph::NodeMap<bool> todo(G,true);

  int num_comp=0;

  for(NodeIt v(G); v!=INVALID; ++v) {

   if ( pos[v]==max_matching.D && todo[v] ) {

      int comp_size=1;

      ++num_comp;

      std::queue<Node> Q;

      Q.push(v);

      todo.set(v,false);

      while (!Q.empty()) {

	Node w=Q.front();	

	Q.pop();

	for(IncEdgeIt e(G,w); e!=INVALID; ++e) {

	  Node u=G.target(e);

	  if ( pos[u]==max_matching.D && todo[u] ) {

	    ++comp_size;

	    Q.push(u);

	    todo.set(u,false);

	  }

	}

      }

      if ( !(comp_size % 2) ) oddcomp=false;  

    }

  }

  check ( oddcomp, "A component of G[D] is not odd." );

  int barrier=0;

  for(NodeIt v(G); v!=INVALID; ++v) {

    if ( pos[v]==max_matching.A ) ++barrier;

  }

  int expected_size=(int)( countNodes(G)-num_comp+barrier)/2;

  check ( size==expected_size, "The size of the matching is wrong." );

  return 0;

}

void random_init()

{

  unsigned int seed = getpid();

  seed |= seed << 15;

  seed ^= time(0);

  srand(seed);

}

int random(int m)

{

  return int( double(m) * rand() / (RAND_MAX + 1.0) );

}

/// Generates a random graph with n nodes and m edges.

/// Before generating the random graph, \c g.clear() is called.

template<typename Graph>

void randomGraph(Graph& g, int n, int m) {

  g.clear();

  std::vector<typename Graph::Node> nodes;

  for (int i=0; i<n; ++i)

    nodes.push_back(g.addNode());

  for (int i=0; i<m; ++i) 

    g.addEdge(nodes[random(n)], nodes[random(n)]);

}