#include <iostream>
#include <omp.h>

using namespace std;

unsigned __int64 fibRecursive(int n)
{
    return n < 3 ? 1 : fibRecursive(n-1) + fibRecursive(n-2);
}

unsigned __int64 fibParallel(int n)
{
    if(n < 3)
    {
        return 1;
    }
    else
	{
		unsigned __int64 firstCall;
		unsigned __int64 secondCall;

#pragma omp task shared(firstCall) firstprivate(n)
		{
			if(n <= 40)
			{
				firstCall = fibRecursive(n - 1);
			}
			else
			{
				firstCall = fibParallel(n - 1);
			}
		}
#pragma omp task shared(secondCall) firstprivate(n)
		{
			if(n <= 40)
			{
				secondCall = fibRecursive(n - 2);
			}
			else
			{
				secondCall = fibParallel(n - 2);
			}
		}
#pragma omp taskwait
		return firstCall + secondCall;
	}
}

int main (int argc, char *argv[])
{
	omp_set_dynamic(0);
    omp_set_num_threads(4);

	auto start = omp_get_wtime();

#pragma omp parallel
    {
#pragma omp single
		{
			cout << fibParallel(50) << endl;
		}
    }

	cout << omp_get_wtime() - start << endl;

	return 0;
}