2 directions list

list2d.cpp

/*
Zadanie polegające na tasowaniu talii kart od 1...n.
Operacja A: przełożenie pierwszej karty na koniec.
Operacja B: przełożenie drugiej karty na koniec.
Wejście: n oraz operacje w jednym stringu (np. abaaabbabaababbaa)
Wyjście: potasowana talia
*/


#include<iostream>
using namespace std;

struct element
{
    element* previous;
    element* next;
    int value;
};

element* first_element = NULL;
element* last_used_element = NULL;
element* final_element = NULL;
element* temp = NULL;

void add_element(int adding_value)
{
    if(first_element == NULL)
    {
        first_element = new element;
        first_element->previous = NULL; //rooting
        first_element->next = NULL;
        first_element->value = adding_value; //add val
        last_used_element = first_element; //temp
    }
    else
    {
        final_element = new element;
        final_element->previous = last_used_element; //connecting
        last_used_element->next = final_element; //connecting
        final_element->next = NULL;
        final_element->value = adding_value; //add val
        last_used_element = final_element; //temp
    }
}

void operation(char op)
{
    if(op == 'A' || op == 'a')
    {
        add_element(first_element->value);
        first_element = first_element->next;
        first_element->previous = NULL;
    }
    if(op == 'B' || op == 'b')
    {
        temp = first_element->next; //temp == 2nd element
        add_element(temp->value); //add 2nd element at the end
        first_element->next = temp->next; //connecting 1st with 3rd element
        temp->previous = first_element; //connecting 3rd (now 2nd) element with 1st aback
        delete temp;
    }
}

void create_deck(int n)
{
    for(int i=1;i<=n;i++)
        add_element(i);
}

void do_operations(string s)
{
    for(int i=0;i<s.length();i++)
        operation(s[i]);
}

void show_list()
{
    element* iterator_of_list = NULL;
    iterator_of_list = first_element;
    while(iterator_of_list!=NULL)
    {
        cout<<iterator_of_list->value<<' ';
        iterator_of_list=iterator_of_list->next;
    }
}

int main()
{
    int n;
    string ops;
    
    cin>>n>>ops; //input
    
    create_deck(n); 
    do_operations(ops);

    show_list();
    return 0;
}