#include <iostream>

using namespace std;

template <typename T>
class List {
public:

    List() : size_(0), head_(nullptr), last_(nullptr) {}

    List(const initializer_list<T>& list) : size_(0), head_(nullptr), last_(nullptr) {
        for (const T& element : list) {
            push_back(element);
        }
    }

    List(const List& other) : size_(0), head_(nullptr), last_(nullptr) {
        Node* temp = other.last_;
        while (temp != nullptr) {
            push_front(temp->value);
            temp = temp->prev;
        }
    }

    List(List&& other) : size_(other.size_), head_(other.head_), last_(other.last_) {
        other.head_ = other.last_ = nullptr;
    }

    List& operator=(const List& other) {
        if (this != &other) {
            clear();
            Node* temp = other.last_;
            while (temp != nullptr) {
                push_front(temp->value);
                temp = temp->prev;
            }
        }
        return *this;
    }

    List& operator=(List&& other) {
        if (this != &other) {
            clear();
            size_ = other.size_;
            head_ = other.head_;
            last_ = other.last_;
            other.head_ = other.last_ = nullptr;
        }
        return *this;
    }

    void push_front(const T& value) {
        if (size_ == 0) {
            last_ = head_ = new Node{ value, nullptr, nullptr };
            size_++;
            return;
        }
        Node* temp = new Node{ value, head_, nullptr };
        head_->prev = temp;
        head_ = temp;
        size_++;
    }

    void push_back(const T& value) {
        if (size_ == 0) {
            last_ = head_ = new Node{ value, nullptr, nullptr };
            size_++;
            return;
        }
        Node* temp = new Node{ value, nullptr, last_ };
        last_->next = temp;
        last_ = temp;
        size_++;
    }

    void pop_front() {
        if (size_ > 0) {
            if (size_ == 1) {
                delete head_;
                last_ = head_ = nullptr;
                size_--;
                return;
            }
            Node* temp = head_;
            head_ = head_->next;
            delete temp;
            head_->prev = nullptr;
            size_--;
        }
    }

    void pop_back() {
        if (size_ > 0) {
            if (size_ == 1) {
                delete head_;
                last_ = head_ = nullptr;
                size_--;
                return;
            }
            Node* temp = last_;
            last_ = last_->prev;
            delete temp;
            last_->next = nullptr;
            size_--;
        }
    }

    void insert(const int index, const T& value) {
        if (index == 0) {
            push_front(value);
            return;
        }
        if (index == size_) {
            push_back(value);
            return;
        }
        if (index > 0 && index < size_) {
            Node* temp = head_;
            for (int i = 0; i < index - 1; i++) {
                temp = temp->next;
            }
            Node* buf = new Node{ value, temp->next, temp };
            temp->next->prev = buf;
            temp->next = buf;
            size_++;
        }
    }

    void erase(const int index) {
        if (index == 0) {
            pop_front();
            return;
        }
        if (index == size_ - 1) {
            pop_back();
            return;
        }
        if (index > 0 && index < size_ - 1) {
            Node* temp = head_;
            for (int i = 0; i < index - 1; i++) {
                temp = temp->next;
            }
            Node* buf = temp->next->next;
            delete temp->next;
            temp->next = buf;
            buf->prev = temp;
            size_--;
        }
    }

    T& operator[] (const int index) {
        if (index >= 0 && index < size_) {
            Node* temp = head_;
            for (int i = 0; i < index; i++) {
                temp = temp->next;
            }
            return temp->value;
        }
    }

    const T& operator[] (const int index) const {
        if (index >= 0 && index < size_) {
            Node* temp = head_;
            for (int i = 0; i < index; i++) {
                temp = temp->next;
            }
            return temp->value;
        }
    }

    bool operator==(const List& other) const {
        if (size_ != other.size_) {
            return false;
        }
        Node* temp = head_;
        Node* other_temp = other.head_;

        while (temp != nullptr) {
            if (temp->value != other_temp->value) {
                return false;
            }
            temp = temp->next;
            other_temp = other_temp->next;
        }
        return true;
    }

    bool operator!=(const List& other) const {
        return !(*this == other);
    }

    int find(const T& value) const {
        int index = 0;
        Node* temp = head_;

        while (temp != nullptr && temp->value != value) {
            temp = temp->next;
            index++;
        }
        if (temp != nullptr) {
            return index;
        }
        return -1;
    }

    T& front() {
        if (head_ != nullptr) {
            return head_->value;
        }
    }

    const T& front() const {
        if (head_ != nullptr) {
            return head_->value;
        }
    }

    T& back() {
        if (last_ != nullptr) {
            return last_->value;
        }
    }

    const T& back() const {
        if (last_ != nullptr) {
            return last_->value;
        }
    }

    void print() {
        Node* temp = head_;
        while (temp != nullptr) {
            cout << temp->value << " ";
            temp = temp->next;
        }
        cout << endl;
    }

    int size() const {
        return size_;
    }

    void clear() {
        while (head_ != nullptr) {
            pop_front();
        }
    }

    ~List() {
        clear();
    }

private:
    struct Node { // двусвязный список состоит из узлов
        T value; // узел хранит информативную часть
        Node* next; // указатель на следующий узел в списке
        Node* prev; // указатель на предыдущий узел
    };

    int size_;
    Node* head_;
    Node* last_;
};



int main() {
    setlocale(LC_ALL, "ru");

    List<int> ls{ 6,7,8,9,10 };
    ls.print();

}