I need help with the following lisp problem, thank you!

If you have any questions please ask!

Write a function compr which takes a list and replaces each run longer than one with a sublist consisting of the count and the item which repeats. If the list has sublists, treat them as single items; don't change them or try to compress the sublists. If an item is not repeated, leave it unchanged, with one exception: an existing item is a sublist beginning with a positive number, and does not repeat, it should be changed to a pair with a repeate count of 1. For instance, a sublist (3 spoons) which does not repeat should be converted to (1 (3 spoons)). The purpose of this rule is to avoid confusion so it is possible to create a reliable decompress function which will always recreate the original list. Here are some examples: lsp> (load "compr. lsp") compr lsp> (compr '(a b w goober goober ccc tom fred fred)) (a bw (2 goober) (3 c) tom (2 fred)) 1sp> (compr '(nothing here to change)) (nothing here to change) lsp> (compr '((a bc)(a bc)(a bc) (def) (4 5 6) (-3 -5 - ((3 (a bc)) (def) (1 (4 5 6)) (-3 -5 -7) 10 12) isp> (compr '(thing thing (a b) (a b) (a b) (ba) thud wumpus) ((2 thing) (3 (a b)) (ba) thud wumpus) lsp> (compr'(oooh oooh oooh oooh oooh)) ((5 oooh)) Use the equal? function to decide if adjacent items are the same. (Don't use , since is only for comparing numbers.) Hints You are free to define any number helper functions in addition to compr, and you will probably need to. I defined a function pref which tells the number of times the first item in a list repeats, like this: lsp> (pref '(a a a b b ccccc)) Isp>(pref '(a b c d)) Isp>(pref '0)