void nqueens(char *config, int n, int i)
{
    char *new_config;
    int j;

    if (i==n)
    {
        #pragma omp atomic
        count++;
    }
    for (j=0; j<n; j++)
    {
        if (i < 1){
            new_config = malloc((i+1)*sizeof(char));
            memcpy(new_config, config, i*sizeof(char));
            #pragma omp task
            {
                if (safe(new_config, i, j))
                {
                    new_config[i] = j;
                    nqueens(new_config, n, i+1);
                }
            }

            #pragma omp taskwait
            free(new_config);
        }else{
            new_config = malloc((i+1)*sizeof(char));
            memcpy(new_config, config, i*sizeof(char));
            if (safe(new_config, i, j))
            {
                new_config[i] = j;
                nqueens_serial(new_config, n, i+1);
            }
            free(new_config);
        }
    }

    return;
}