[c++,algorithm]3_fpTree

//fpTree.h

#ifndef FPTREE_H#define FPTREE_H#include <iostream>#include <memory>#include "itemset.h"#include "transaction.h"namespace fptSpace{class fpTree ;class fpTree{public :fpTree ( ordered_itemset items ,transaction_database &db ) ;fpTree ( const fpTree & );struct stats {stats () ;std::size_t size ;std::size_t n_leaves ;std::size_t height ;} ;stats get_stats () const ;class node ;typedef std::shared_ptr<node> nodeptr ;const ordered_itemset   item_order ;private:std::unordered_map<item_type , nodeptr> roots ;struct header {nodeptr head ;nodeptr tail ;} ;std::unordered_map<item_type,header> headerList ;} ;}#endif //FPTREE_H

//fpTree.cpp

#include <unordered_set>#include <limits>#include <cassert>#include <memory>#include "fpTree.h" using fptSpace::fpTree ;class fpTree::node : public std::enable_shared_from_this<node>{public :node ( const ordered_itemset &item_order ,item_type _item , std::weak_ptr<node> p = std::weak_ptr<node>() ) :item ( _item ),counter(0) ,parent( parent),item_order(item_order) {}nodeptr operator[] (item_type) ;void increment_count () {counter++ ;} item_type item ;std::size_t counter ;std::weak_ptr<node> parent ;std::unordered_map<item_type, nodeptr > children ;const ordered_itemset &item_order ;};fpTree::nodeptr fpTree::node::operator[] (std::string item ){nodeptr &retval = children[item] ;if ( !retval )retval = nodeptr ( new node(item_order ,item, shared_from_this() )) ;return retval ;}fpTree::fpTree (fptSpace::ordered_itemset _items , fptSpace::transaction_database &db ):item_order ( std::move(_items) ){for ( const transaction &trans : db ){nodeptr current ;//first find the first node (frequency max)//from the travering transaction (itemset )auto i = item_order.begin () ;for ( ; i != item_order.end() ;i++ )if (trans.find(i->_item) != trans.end())break ;//we find the first node in transaction //pointed by the i , then if  i not null //search it in the roots (first level in fpTree )//else if the i is null , we create a node for i//and insert it into the roots which with the type//of  unordered_map<item , nodeptr>assert (i != item_order.end()) ;{//construct root if non-existentnodeptr &root = roots[i->_item] ;if ( !root )root = nodeptr( new node (item_order, i->_item)) ;current = root ;}current->increment_count() ;i++ ;//traverse through the rest elements in current transactionfor ( ; i != item_order.end() ; i++ ){if ( trans.find(i->_item) == trans.end() )continue ;current = (*current)[i->_item] ;current->increment_count() ;}}}namespace{void traverse ( const fpTree::nodeptr ¤t_node ,std::size_t height , fpTree::stats &stats ){++stats.size ;if ( current_node->children.empty() ){//reach leaf ++stats.n_leaves ;stats.height = std::max(stats.height , height ) ;}else{for ( const auto &i : current_node->children)traverse ( i.second , height+1 , stats) ; }}}fpTree::stats fpTree::get_stats() const{fpTree::stats stats ;for ( const auto &i : roots )traverse(i.second , 1 , stats ) ;return stats ;}fpTree::stats::stats() :size(0) ,n_leaves(0),height(0) {}

//Main.cpp

#include <cstdio>#include <cstdlib>#include <iostream>#include "fileParser.h"#include "parser.h"#include "fpTree.h"#include "memChecker.h"using namespace std ;int main ( void ){string filename ("d:\\test\\a.dat") ;/*parser::transaction_database database ;database = parser::parseFile(filename) ; cout<<endl<<"here are all the items in transaction database "<<endl;for ( const auto &i : database )  //traverse vector < vector <string> >  ;  i   is  type of  vector<string>for (const auto &j : i )//traverse vector <string >;  j is the type of string  , out  put directly is ok cout<<j<<endl ;`*/fptSpace::transaction_database trans_db = fptSpace::parseFromFile(filename) ;fptSpace::itemset itemSet = trans_db.extract_itemset() ;int total_item_counter = itemSet.size() ;double min_support ;int sup_threshold ;cout<<"input min support ( min_sup < 1 )"<<endl;cin >> min_support ;sup_threshold = (int) (min_support*total_item_counter );itemSet.prune(sup_threshold) ;    //fptSpace::ordered_itemset ordered_item_set = itemSet.get_ordered() ;fptSpace::fpTree tree ( itemSet.get_ordered() , trans_db) ;fptSpace::fpTree::stats stats = tree.get_stats() ;std::cout<<"File :"<<filename<< std::endl <<"Threshold:"<<min_support<<std::endl <<"Number of nodes:  "<<stats.size<<std::endl <<"Number of leaves:  "<<stats.n_leaves<<std::endl <<"          Height:"<<stats.height  <<std::endl  <<"Max memory usage:"<<fptSpace::get_maxMem_kb()<<" kb "<<std::endl ; system("pause") ;return 0 ;}

//有时间再注释，其中的smart 指针和命名空间还有复杂结构类型的STL 将各写一个专题进行学习实验

//快要考试了，要看书了