1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/algs4-c++/src/Deque.cpp	Wed Jun 10 15:44:42 2015 -0500
     1.3 @@ -0,0 +1,215 @@
     1.4 +// g++ -D DEQUE_MAIN -std=c++0x Deque.cpp
     1.5 +// g++ -D DEQUE_MAIN -std=c++11 Deque.cpp
     1.6 +
     1.7 +
     1.8 +#include "Deque.hpp"
     1.9 +
    1.10 +#include <cassert>
    1.11 +#include <cstddef>
    1.12 +
    1.13 +#include <iostream>
    1.14 +
    1.15 +template <typename T>
    1.16 +Deque<T>::Deque( void ) :
    1.17 +    N (0),
    1.18 +    first (nullptr),
    1.19 +    last (nullptr)
    1.20 +    {
    1.21 +    }
    1.22 +    
    1.23 +template <typename T>
    1.24 +Deque<T>::~Deque( void ) {
    1.25 +    assert( N == 0 );  // Catch the potential memory leak.
    1.26 +    while ( first ) {
    1.27 +        Node *next = first->next;
    1.28 +        delete first;
    1.29 +        first = next;
    1.30 +        }
    1.31 +    }
    1.32 +
    1.33 +template <typename T>
    1.34 +void Deque<T>::push_right( T &item ) {
    1.35 +    Node * node = new Node();
    1.36 +    node->item = item;
    1.37 +    node->next = nullptr;
    1.38 +    node->prev = nullptr;
    1.39 +
    1.40 +    if ( last ) {
    1.41 +        last->next = node;
    1.42 +        node->prev = last;
    1.43 +        last = node;
    1.44 +        }
    1.45 +    else {
    1.46 +        last = first = node;
    1.47 +        }
    1.48 +
    1.49 +    N++;
    1.50 +    }
    1.51 +
    1.52 +template <typename T>
    1.53 +void Deque<T>::push_left( T &item ) {
    1.54 +    Node * node = new Node();
    1.55 +    node->item = item;
    1.56 +    node->next = nullptr;
    1.57 +    node->prev = nullptr;
    1.58 +
    1.59 +    if ( first ) {
    1.60 +        node->next = first;
    1.61 +        first->prev = node;
    1.62 +        first = node;
    1.63 +        }
    1.64 +    else {
    1.65 +        last = first = node;
    1.66 +        }
    1.67 +
    1.68 +    N++;
    1.69 +    }
    1.70 +
    1.71 +template <typename T>
    1.72 +T Deque<T>::pop_left( void ) {
    1.73 +    assert( N > 0 );
    1.74 +
    1.75 +    T item = first->item;
    1.76 +
    1.77 +    Node *old = first;
    1.78 +    if ( first->next )
    1.79 +        first->next->prev = nullptr;
    1.80 +    first = first->next;
    1.81 +    delete old;
    1.82 +    N--;
    1.83 +
    1.84 +    if ( ! first )
    1.85 +        last = nullptr;
    1.86 +
    1.87 +    return item;
    1.88 +    }
    1.89 +
    1.90 +template <typename T>
    1.91 +T Deque<T>::pop_right( void ) {
    1.92 +    assert( N > 0 );
    1.93 +
    1.94 +    T item = last->item;
    1.95 +
    1.96 +    Node *old = last;
    1.97 +    if ( last->prev )
    1.98 +        last->prev->next = nullptr;
    1.99 +    last = last->prev;
   1.100 +    delete old;
   1.101 +    N--;
   1.102 +
   1.103 +    if ( ! last )
   1.104 +        first = nullptr;
   1.105 +
   1.106 +    return item;
   1.107 +    }
   1.108 +
   1.109 +template <typename T>
   1.110 +bool Deque<T>::is_empty( void ) {
   1.111 +    return N == 0;
   1.112 +    }
   1.113 +
   1.114 +template <typename T>
   1.115 +size_t Deque<T>::size( void ) {
   1.116 +    return N;
   1.117 +    }
   1.118 +
   1.119 +template <typename T>
   1.120 +typename Deque<T>::iterator Deque<T>::begin( void ) {
   1.121 +    return Deque<T>::iterator( first );
   1.122 +    }
   1.123 +
   1.124 +template <typename T>
   1.125 +typename Deque<T>::iterator Deque<T>::end( void ) {
   1.126 +    return Deque<T>::iterator( nullptr );
   1.127 +    }
   1.128 +
   1.129 +
   1.130 +////////////////////////////////////////////////////////////////////////////////
   1.131 +
   1.132 +template <typename T>
   1.133 +Deque<T>::iterator::iterator( Node *c ) :
   1.134 +    curr (c)
   1.135 +    {
   1.136 +    }
   1.137 +
   1.138 +template <typename T>
   1.139 +typename Deque<T>::iterator & Deque<T>::iterator::operator++() {
   1.140 +    if ( this->curr != nullptr ) {
   1.141 +        this->curr = this->curr->next;
   1.142 +        }
   1.143 +    return *this;
   1.144 +    }
   1.145 +
   1.146 +template <typename T>
   1.147 +typename Deque<T>::iterator Deque<T>::iterator::operator++( int ) {
   1.148 +    auto t = Deque<T>::iterator( *this );
   1.149 +
   1.150 +    if ( this->curr != nullptr ) {
   1.151 +        this->curr = this->curr->next;
   1.152 +        }
   1.153 +    return t;
   1.154 +    }
   1.155 +
   1.156 +template <typename T>
   1.157 +T Deque<T>::iterator::operator*() {
   1.158 +    return this->curr->item;
   1.159 +    }
   1.160 +
   1.161 +template <typename T>
   1.162 +bool Deque<T>::iterator::operator!=( typename Deque<T>::iterator other ) {
   1.163 +    return this->curr != other.curr;
   1.164 +    }
   1.165 +
   1.166 +
   1.167 +////////////////////////////////////////////////////////////////////////////////
   1.168 +
   1.169 +#ifdef DEQUE_MAIN
   1.170 +
   1.171 +#include <iostream>
   1.172 +
   1.173 +int main ( int argc, char **argv ) {
   1.174 +
   1.175 +    Deque<long> deque;
   1.176 +    bool left = true;
   1.177 +
   1.178 +    long i;
   1.179 +    while ( ! std::cin.eof() ) {
   1.180 +        std::cin >> i;
   1.181 +        if ( std::cin.good() )  {
   1.182 +            if ( left ) {
   1.183 +                deque.push_left( i );
   1.184 +                left = false;
   1.185 +                }
   1.186 +            else {
   1.187 +                deque.push_right( i );
   1.188 +                left = true;
   1.189 +                }
   1.190 +            }
   1.191 +        }
   1.192 +
   1.193 +    std::cout << "Deque has " << deque.size() << " entries." << std::endl;
   1.194 +
   1.195 +    for ( auto iter = deque.begin(); iter != deque.end(); ++iter ) {
   1.196 +        std::cout << *iter << std::endl;
   1.197 +        }
   1.198 +
   1.199 +    std::cout << "Dequeuing entries..." << std::endl;
   1.200 +
   1.201 +    left = true;
   1.202 +    while ( ! deque.is_empty() ) {
   1.203 +        if ( left ) {
   1.204 +            i = deque.pop_left();
   1.205 +            left = false;
   1.206 +            }
   1.207 +        else {
   1.208 +            i = deque.pop_right();
   1.209 +            left = true;
   1.210 +            }
   1.211 +        std::cout << i << std::endl;
   1.212 +        }
   1.213 +
   1.214 +    std::cout << "Deque has " << deque.size() << " entries." << std::endl;
   1.215 +
   1.216 +    }
   1.217 +
   1.218 +#endif

     2.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     2.2 +++ b/algs4-c++/src/Deque.hpp	Wed Jun 10 15:44:42 2015 -0500
     2.3 @@ -0,0 +1,71 @@
     2.4 +#ifndef DEQUE_HPP
     2.5 +#define DEQUE_HPP
     2.6 +
     2.7 +#include <cstddef>
     2.8 +
     2.9 +// Linked list based deque after Sedgewick and Wayne, Algorithms 4th ed, Algorithm 1.3
    2.10 +
    2.11 +template <typename T>
    2.12 +class Deque {
    2.13 +
    2.14 +private:
    2.15 +
    2.16 +    ////////////////////////////////////
    2.17 +    class Node {
    2.18 +    public:
    2.19 +        T item;
    2.20 +        Node *next;
    2.21 +        Node *prev;
    2.22 +        };
    2.23 +
    2.24 +public:
    2.25 +
    2.26 +    ////////////////////////////////////
    2.27 +    class iterator;
    2.28 +    friend class iterator;
    2.29 +    class iterator {
    2.30 +
    2.31 +    public:
    2.32 +
    2.33 +        iterator( Node *c );
    2.34 +
    2.35 +        iterator& operator++();
    2.36 +        iterator operator++(int);
    2.37 +
    2.38 +        T operator*();
    2.39 +        bool operator!=( typename Deque<T>::iterator );
    2.40 +
    2.41 +    private:
    2.42 +
    2.43 +        Node *curr;
    2.44 +        };
    2.45 +
    2.46 +    ////////////////////////////////////
    2.47 +
    2.48 +    Deque( void );
    2.49 +    ~Deque( void );
    2.50 +
    2.51 +    void push_left( T &item );
    2.52 +    void push_right( T &item );
    2.53 +    T pop_left( void );
    2.54 +    T pop_right( void );
    2.55 +
    2.56 +    bool is_empty( void );
    2.57 +    size_t size( void );
    2.58 +
    2.59 +    iterator begin( void );
    2.60 +    iterator end( void );
    2.61 +
    2.62 +
    2.63 +private:
    2.64 +
    2.65 +    size_t N;
    2.66 +    Node *first;
    2.67 +    Node *last;
    2.68 +
    2.69 +    };
    2.70 +
    2.71 +
    2.72 +
    2.73 +#endif
    2.74 +