tpl_test_acyclique.H

/* Aleph-w

     / \  | | ___ _ __ | |__      __      __
    / _ \ | |/ _ \ '_ \| '_ \ ____\ \ /\ / / Data structures & Algorithms
   / ___ \| |  __/ |_) | | | |_____\ V  V /  version 1.9b
  /_/   \_\_|\___| .__/|_| |_|      \_/\_/   https://github.com/lrleon/Aleph-w
                 |_|         

  This file is part of Aleph-w library

  Copyright (c) 2002-2018 Leandro Rabindranath Leon & Alejandro Mujica

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
# ifndef TPL_TEST_ACYCLIQUE_H
# define TPL_TEST_ACYCLIQUE_H

namespace Aleph {



      template <class GT, class SA = Dft_Show_Arc<GT>> 
class Is_Graph_Acyclique
{
  SA & sa;

  bool is_acyclique(typename GT::Node * curr)
  {
    if (IS_NODE_VISITED(curr, Test_Cycle)) 
      return false;

    NODE_BITS(curr).set_bit(Test_Cycle, true); // marcar nodo

    for (Node_Arc_Iterator<GT, SA> i(curr, sa); i.has_curr(); i.next_ne())
      {
        typename GT::Arc * arc = i.get_current_arc_ne();
        if (IS_ARC_VISITED(arc, Test_Cycle)) 
          continue; 

        ARC_BITS(arc).set_bit(Test_Cycle, true); 

        if (not is_acyclique(i.get_tgt_node())) 
          return false;
      }

    // todos los arcos recorridos sin encontrar ciclo ==>
    // el grafo es acíclico pasando por curr_node
    return true; 
  }

  bool is_acyclique(GT & g, size_t num_arcs)
  {
    if (g.is_digraph())
      throw std::domain_error("is_graph_acyclique() does not work for digraps");

    if (num_arcs >= g.get_num_nodes()) 
      return false; 

    g.reset_bit_arcs(Test_Cycle);
    g.reset_bit_nodes(Test_Cycle);

    for (typename GT::Node_Iterator it(g); it.has_curr(); it.next_ne()) 
    {
      typename GT::Node * curr = it.get_current_node_ne();
      if (IS_NODE_VISITED(curr, Test_Cycle)) 
        continue; 

      if (not is_acyclique(curr)) 
        return false;
    }

  return true;
}

public:
  
  Is_Graph_Acyclique(SA && __sa = SA()) : sa(__sa) { /* empty */ }

  Is_Graph_Acyclique(SA & __sa) : sa(__sa) { /* empty */ }

  bool operator () (GT & g, size_t num_arcs) 
  {
    return is_acyclique(g, num_arcs);
  }

  bool operator () (GT & g) 
  {
    return is_acyclique(g, g.get_num_arcs());
  }
};

      template <class GT, class SA = Dft_Show_Arc<GT>> 
class Has_Cycle
{
  SA & sa;

public:

  Has_Cycle(SA && __sa = SA()) : sa(__sa) { /* empty */ }

  Has_Cycle(SA & __sa) : sa(__sa) { /* empty */ }

  bool operator () (GT & g) const
  {
    return not Is_Graph_Acyclique <GT, SA> (sa) (g);
  }

  bool operator () (GT & g, size_t num_arcs) const
  {
    return not Is_Graph_Acyclique <GT, SA> (sa) (g, num_arcs);
  }
};




} // end namespace Aleph

# endif //  TPL_TEST_ACYCLIQUE_H