Mergesort
•Now we need to remember that each call
to mergesort
calls itself twice.
–How many levels of recursion are there?
–Remember we continue halving the list
of numbers
until the result is a piece with only 1 number in it.
–Therefore, if there are N items in your
list, there will be either log2N levels (if N is a power of 2) and 1+log2N
(if N is NOT a power of 2).