double trapez_area(f, left, right) {
    return (f(left) + f(right)) * (right - left) / 2;
}

double area(f, left, right) {
    aria_totala = trapez_area(f, left, right);
    mid = (left + right) / 2;
    aria_stanga = trapez_area(f, left, mid);
    aria_dreapta = trapez_area(f, mid, right);

    if (abs(aria_totala - (aria_stanga + aria_dreapta)) < eps)
        return aria_totala
    return area(f, left, mid) + area(f, mid, right)
}