An algorithm ALG consists of two tunable sub$-$algorithms ALGA and ALGB, which have to be executed serially $($i$.$e$.,$ one run of ALG involves first executing ALGA followed by ALGB$).$ Moreover, given any function f$($n$),$ we can tune the two algorithms such that ALGA takes time O$($f$($n$))$ and ALGB takes time O$($n$2/$f$($n$)).$ How should we choose f to minimize the overall runtime of ALG$($i$.$e$.,$ to ensure the runtime of ALG is O$($h$($n$))$ for the smallest$-$growing function h$)?$ How would your answer change if ALGA and ALGB could be executed in parallel, and we have to wait for both to finish?