problem statement
do it in two passes
by diffinition without ...
tricky
in addition
duplicate
what we really want to do is
go through how to do it in detail modify the
interleave with seperate into ...
be ..dec node itself
this is taking linear space in addtion
we can come up with a new alogrithm that are going to take constant space in addition.
the way we can do even better is by ....
time and space can't be safed at the same time. either running time friendly or space resource friendly