Balls Game

/* игра с двойно свързана циклична структура - прочитане на числа (брой топчета), които държат в ръце хора подредени в кръг. първият дава по едно от своите топчета на всички по часовниковата стрелка. когато му свършат “предава щафетата” на следващия след него. играта свършва, когато се достигне до играч, който няма топчета. */

#include <iostream>
#include <fstream>

using namespace std;

template <typename T>
class DoubleLink
{
        DoubleLink* previous;
        T payload;
        DoubleLink* next;

public:
        DoubleLink ()
        {
                previous = this;
                next = this;
        }

        DoubleLink (T init)
        {
                previous = this;
                next = this;
                payload = init;
        }

        void AddLink (DoubleLink* new_elem)
        {
                DoubleLink* a = this;
                DoubleLink* b = this->next;
                a->next = new_elem;
                new_elem->previous = a;

                b->previous = new_elem;
                new_elem->next = b;

        }

        inline DoubleLink* GetPrevious()
        {
                return previous;
        }

        inline DoubleLink* GetNext()
        {
                return next;
        }

        inline DoubleLink* SetNext(DoubleLink* new_next )
        {
                return (next = new_next);
        }


        inline DoubleLink* SetPrev(DoubleLink* new_prev )
        {
                return (previous = new_prev);
        }

        inline T GetData ()
        {
                return payload;
        }

        inline T SetData (T new_data)
        {
                return (payload = new_data);
        }

        void Delete ()
        {
                if ( this != this->GetNext() ) {
                        this->GetPrevious()->SetNext( this->GetNext() );
                        this->GetNext()->SetPrev( this->GetPrevious() );
                }

                delete this;
        }
};

void PrintElements (DoubleLink<int> *dl)
{
        DoubleLink<int> *curr = dl->GetNext();

        do
        {
                cout << curr->GetPrevious()->GetData() << " ";
                curr = curr->GetNext();
        }
        while (curr != dl);

        cout << curr->GetPrevious()->GetData() << endl;
}

void PlayGame (DoubleLink<int>* dl)
{
        bool flag = true;
        DoubleLink<int>* curr = dl;

        cout << "-- start game -- " << endl;

        while ( curr != curr->GetNext() ) {

                while ( curr->GetData() ) {
                        DoubleLink<int>* p = curr->GetNext();

                        cout << (flag ? '>' : '<');

                        while (curr->GetData() ) {
                                curr->SetData( curr->GetData() - 1);
                                p->SetData (p->GetData() + 1);
                                if (flag)
                                        p = p->GetNext();
                                else
                                        p = p->GetPrevious();
                        }

                        curr = p;
                        flag = !flag;

                        PrintElements(dl);
                }

                DoubleLink<int>* newc = flag ? curr->GetNext() : curr->GetPrevious();
                if (curr == dl)
                        dl = newc;
                curr->Delete();
                curr = newc;
        }
}


int main ()
{
        ifstream file ("input.txt");
        if (!file)
        {
                cerr << "File could not be opened.\n";
                return -1;
        }

        DoubleLink<int> *curr = NULL;

        while (!file.eof())
        {
                int x;
                file >> x;
                if (curr)
                        curr->AddLink(new DoubleLink<int> (x));
                else
                        curr = new DoubleLink<int> (x);

                curr = curr->GetNext();
        }

        PrintElements(curr->GetNext());
        PlayGame(curr->GetNext());

//      system ("PAUSE");
        return 0;
}