# [plt-scheme] HtDP 26.1.2

Hi all --
Question about HtDP function "merge-neighbors:"
Link to exercise: http://www.htdp.org/2003-09-26/Book/curriculum-Z-H-33.html#node_sec_26.1
The text describes the contract for "merge-neighbors" as a function
which "merges pairs of neighboring lists. More specifically, it
consumes a list of lists (of numbers) and merges neighbors. For
example,
(equal? (merge-all-neighbors (list (list 2) (list 5) (list 9) (list
3)))
(list (list 2 5) (list 3 9))) "
In the example, however, it seems that in addition to merging pairs of
neighboring lists, "merge-neighbors" also sorts each pair of lists in
ascending order before combining them. In other words --
(check-expect (merge-all-neighbors (list (list 9) (list 1)) (list
(list 1 9))?
Further, suppose the function input is a list of list-of-numbers in
descending order --
(define list1 (list (list 9) (list 7) (list 5) (list 3))).
In this case, does "merge-all-neighbors" evaluate list1 to (list (list
7 9) (list 3 5)) --
-- or to (list (list 3 5) (list 7 9)).
Thanks!
Dave Yrueta