generate_df_tree.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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  SOFTWARE.
*/
 
 
#ifndef GENERATE_DF_TREE_H
#define GENERATE_DF_TREE_H
 
#include <tpl_graph_utils.H>
#include <tpl_tree_node.H>
#include <generate_tree.H>
 
static long global_counter = 0;
 
struct Clave
{
  int key;    
  long count; 
  long low;   
};
 
struct Clave_Igual
{
  bool operator () (const Clave & c1, const Clave & c2) const
  {
    return c1.key == c2.key;
  }  
};
 
struct Convertir
{
  void operator () (Grafo::Node * tnode, Tree_Node<Clave> * t)
  {
    Grafo::Node * gnode = static_cast<Grafo::Node *>(NODE_COOKIE(tnode));
 
    Clave & clave = t->get_key();
    clave.key   = tnode->get_info().clave;
    clave.count = gnode->get_info().df;
    clave.low   = gnode->get_info().low;
  }
};
 
struct Write_Node
{
  static const size_t Buf_Size = 512;
 
  std::string operator () (Tree_Node<Clave> * p)
  {
    char str[2];
    str[0] = p->get_key().key;
    str[1] = '\0';
    return std::string(str);
  }
};
 
struct Write_Df
{
  static const size_t Buf_Size = 512;
 
  std::string operator () (Tree_Node<Clave> * p)
  {
    char buf[Buf_Size];
    snprintf(buf, Buf_Size, "(%c,%ld)", p->get_key().key, p->get_key().count);
    return std::string(buf);
  }
};
 
struct Write_Low
{
  static const size_t Buf_Size = 512;
 
  std::string operator () (Tree_Node<Clave> * p)
  {
    char buf[Buf_Size];
 
    if (p->get_key().low >= 0)
      snprintf(buf, Buf_Size, "%d,%ld,%ld", 
               p->get_key().key, p->get_key().count, p->get_key().low);
    else
      snprintf(buf, Buf_Size, "%d,%ld,-", 
               p->get_key().key, p->get_key().count);
 
    return std::string(buf);
  }
};
 
inline void visitar_df(Grafo &, Grafo::Node * nodo, Grafo::Arc *)
{
  nodo->get_info().df = global_counter++;
}
 
inline void visitar_low(Grafo &, Grafo::Node * nodo, Grafo::Arc *)
{
  nodo->get_info().low = reinterpret_cast<long>(nodo->cookie);
}
 
 
template <class GT, class Key>
void write_df_low_tree(GT & g, typename GT::Node * src, std::ofstream & f)
{
  // Compute cut nodes (articulation points)
  DynDlist<typename GT::Node*> node_list = compute_cut_nodes(g);
 
  depth_first_traversal(g, src, &visitar_df);  // Copy df numbers
  depth_first_traversal(g, src, &visitar_low); // Copy low-link values
 
  Grafo tree = find_depth_first_spanning_tree(g, src);
 
  // Compute non-tree arcs (back edges)
  DynDlist<No_Tree_Arc> arc_list;
  generate_non_tree_arcs(g, arc_list);
 
  typename GT::Node * td = static_cast<typename GT::Node *>(NODE_COOKIE(src));
 
  Tree_Node<Key> * rd = Graph_To_Tree_Node () <Grafo, Key, Convertir>(tree, td);
 
  generate_tree<Tree_Node<Key>, Write_Low>(rd, f);
 
  write_non_tree_arcs(arc_list, rd, f);
}
 
#endif // GENERATE_DF_TREE_H