#include <iostream>
#include <cstring>

using std::cout;
using std::endl;

struct Node
{
    int value{0};
    Node* next{nullptr};
};



struct Lista
{
    int count{0};
    Node *head{ nullptr };
    Node *tail{ nullptr };

    void print()
    {
         if (!head)
         {
             cout << "[]" <<endl;
             return;
         }
         int index = 0;
         Node* current = head;
         cout <<count << " [" ;
         while (current)
         {
            cout <<current->value;
            index++;
            if (index <count) cout << ",";

            current = current->next;
         }
         cout <<"]" <<endl;
    }

    void push_front(int value)
    {
         Node* node = new Node();
         node->value = value;
         if(!head)
         {
             head = node;
             tail = node;
         }else
         {
            node->next = head;
            head = node;
         }
         count++;
    }

    void push_back(int value)
    {

        Node* node = new Node();
         node->value = value;
         if(!head)
         {
             head = node;
             tail = node;
         }else
         {
             tail->next = node;
             tail = node;
         }
         count++;



    }


    bool pop_front()
    {
        if (!head) return false;

        Node* tmp = head->next;
     //   cout << "delete:" << head->value << endl;
        delete head;
        head = tmp;
        count--;
        return true;
    }

    bool pop_back()
    {
        if (!head) return false;

        if (count==1)
        {
            return pop_front();
        }


        Node* current = head;
        Node* prev = nullptr;
        while(current->next)
        {
            prev = current;
            current = current->next;
        }
        if(prev)
        {
            Node* del = prev->next;
            tail = prev;
            tail->next = nullptr;
            cout << del->value << endl;
            delete del;
        }

        count--;

        return true;
    }


    void clear()
    {


        Node* tmp=head;
        while (head)
        {
            tmp = head->next;
        //    cout << "delete:" << head->value << endl;
            delete head;
            head = tmp;
        }
        count = 0;
    }


    bool insert(int index, int value)
    {
        if(index<=0)
        {
            push_front(value);
            return true;
        }
        if(index>=count)
        {
            push_back(value);
            return true;
        }

        Node* prev = head;
        Node* current = nullptr;
        for (int i = 0; i <= index - 1; i++)
        {
            current = prev;
            prev = prev->next;
        }

        Node* node = new Node();
        node->value = value;
        node->next = prev;
        current->next = node;
        count++;

        // cout<<"index: " << index << endl;
        // cout<<"prev: " << prev->value << endl;
        // cout<<"currn: " << current->value << endl;

        return false;
    }


    bool remove(int index)
    {
        if (!head) return false;
        if (index <= 0) return pop_front();
        if (index >= count) return pop_back();
        Node* prev = head;
        Node* current = nullptr;
        for (int i = 0; i <= index - 1; i++)
        {
            current = prev;
            prev = prev->next;
        }

        // cout<<"prev: " << prev->value << endl;
        // cout<<"currn: " << current->value << endl;

        current->next = prev->next;
        delete prev;

        count--;


        return false;
    }
};

int main()
{

    Lista lista;
    for (int i = 0; i <= 5;i++)
        lista.push_back(i);


    lista.insert(5, 100);

    // lista.remove(5);


    // lista.push_back(1);

    //  lista.pop_back();
    // lista.pop_back();
    // lista.pop_back();
    // lista.pop_back();

    lista.print();

    lista.clear();
    return 0;
}