Question 90
Find all functions $f: \mathbb{Z} \to \mathbb{Z}$ such that
(i) $f(f(n)) = f(n+1)$ for all $n \in \mathbb{Z}$;
(ii) $f(2009n + 2008) = 2009 \cdot f(n)$ for all $n \in \mathbb{Z}$.
(i) $f(f(n)) = f(n+1)$ for all $n \in \mathbb{Z}$;
(ii) $f(2009n + 2008) = 2009 \cdot f(n)$ for all $n \in \mathbb{Z}$.