int findIndex$($String s$,$ int low, int high$)$

This method takes as parameters a String, and two indices that indicate the search range. It

finds the index of the consecutive pair that begins with the highest order letter $($alphabetically$,$

e$.$g$.,$ a is the lowest, and z is the highest$).$ If no such pairs exist, return $-1$ as the index. The

method uses a divide$-$and$-$conquer algorithm to find and return this index. For example, in

string $$rabhxzdpqrovwa$,$ the pairs $$ab$,$pq$,$qr$,$ and $$vw$$ are consecutive pairs $($first letter is

the immediate predecessor of the second letter$),$ and $$v$$ has the highest order $($out of $$a$,$p$,$

$$q$,$ and $$v$),$ so the index of $$v$$ is returned, which is $11.$