We'll look at two performance tweaks for the Power1 class shown previously.
First, we need to switch to a better algorithm. Then, we will require a better algorithm combined with memoization, which involves a cache; therefore, the function becomes stateful. This is where callable objects shine.
The first modification is to use a divide-and-conquer design strategy. The previous version chopped the computation of 
into 
steps; the loop carried out n individual multiplication operations. If we can find a way to split the problem ...
