I have derived that the required number of operations in my algorithm is $Y(a)$, where $a>0$ is the concerned parameter.
However, $Y(a)$ is not a closed-form expression w.r.t. $a$.
But I find that $Y(a)\leq P(a)$, and $P(a)$ can be expressed as a closed-form w.r.t. $a$, that is $P(a)=a^2+1$.
So, can I say that my algorithm has a computation complexity $\mathcal{O}(a^2)$?
If not, how can I describe the computation complexity?
Thanks for any helpful advice! ^v^