Trie.hpp

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/***************************************************************************
                          Trie.hpp  -  description
                             -------------------
    begin                : cs dec 26 2002
    copyright            : (C) 2002 by Ferenc Bodon
    email                : bodon@mit.bme.hu
 ***************************************************************************/

#ifndef Trie_HPP
#define Trie_HPP

#include "common.hpp"
#include <vector>
#include <set>

using namespace std;

class Apriori_Trie;
class Trie;

struct Edge
{
   itemtype label;
   Trie* subtrie;
};

class Trie
{
friend class Apriori_Trie;

public:

   Trie( const unsigned long init_counter );

   const Trie* is_included( const set<itemtype>& an_itemset, 
                            set<itemtype>::const_iterator item_it ) const;

   void find_candidate( vector<itemtype>::const_iterator it_basket_upper_bound, 
                        const itemtype distance_from_candidate,
                        vector<itemtype>::const_iterator it_basket, 
                        const unsigned long counter_incr=1);

   void delete_infrequent( const unsigned long min_occurrence, 
                           const itemtype distance_from_candidate,
                           unsigned long& nr_of_freq_itemsets );

   ~Trie();

private:

   void add_empty_state( const itemtype item, 
                         const unsigned long init_counter=0 );

public:
   // No public members

private:

   unsigned long counter;

   vector<Edge> edgevector;
};


#endif

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