Other
CPSC110 problem set 7 solution
- Course
- CPSC 110 (CPSC110)
- Institution
- University Of British Columbia (UBC )
complete solution for problem set 7
[Show more]
Seller
Follow
Content preview
(@cwl skim121)(@problem 1)
;; There is a primi7ve type called 1String, defined as follows:
;;
;; 1String is String
;; interp. a 1String represents a single leDer
;; CONSTRAINT: any 1String is only one leDer long
(@htdd ListOf1String)
;; ListOf1String is one of:
;; - empty
;; - (cons 1String ListOf1String)
;; interp. a sequence of leDers
(define L1 empty)
(define L2 (list "a" "B" "c"))
(@htdd Opera7ons)
;; Opera7ons is one of:
;; - empty
;; - (cons "keep" Opera7ons)
;; - (cons "space" Opera7ons)
;; - (cons "remove" Opera7ons)
;; interp. a sequence of opera7ons to apply to a list of 1String
;; "keep" means keep the corresponding leDer
;; "space" means replace the corresponding leDer with a " "
;; "remove" means remove the corresponding leDer
;;
;; In this problem you will design a func7on called decoder, that will
;; decode encrypted messages! Very poorly encrypted messages. The func7on
;; consumes a ListOf1String (l) and Opera7ons (ops) in that order. The
;; func7on should produce a String which is the result of applying the
;; given opera7ons to the successive 1String and joining the resul7ng
;; leDers together.
;;
;; For example:
;; (decoder (list "i" "k" "l" "h" "a" "m" "k" "s" "a" "r" "m")
;; (list "keep" "remove" "remove" "space" "keep" "keep"
;; "space" "keep" "keep" "remove"))
;;
;; should produce "i am sam"
, ;;
;; No7ce that some of the leDers were kept, some were replaced with a space,
;; and some were removed.
;;
;; If ops runs out of opera7ons before the end of the 1String, then all
;; the remaining leDers in l are kept.
;;
;; If l runs out of 1String first, then the remaining opera7ons in ops are
;; ignored.
;;
;; Example 2:
;; (decoder (list "f" "a" "d" "e")
;; (list "remove" "keep" "space" "keep" "remove" "keep" "space"))
;;
;; should produce "a e"
;;
;; You MUST SOLVE THIS AS A 2-ONE-OF PROBLEM and your solu7on must include
;; a table. You must use numbers to show the correspondence between table cells
;; and cond QA pairs. By this, we mean you should NUMBER the table cells and
;; NUMBER the corresponding cond QA pairs with the same numbers (as was done
;; in lecture). If you can simplify the table you should. Finally, it is
;; IMPERATIVE that your cond ques7ons only include the kinds of ques7ons that
;; the data driven template rules produce, other condi7onal behaviour must go
;; into the cond answers. (This is the rule about not edi7ng template ques7ons
;; carried over into 2-one-of problems.)
;;
(@htdf decoder) ;!!! uncomment this when you start your func7on design
(@signature ListOf1String Opera7ons -> String)
;; produce list of string based on given opera7on
(check-expect (decoder empty empty) "")
(check-expect (decoder empty (list "keep")) "")
(check-expect (decoder empty (list "space")) "")
(check-expect (decoder empty (list "remove")) "")
(check-expect (decoder (list "a") empty) "a")
(check-expect (decoder (list "h" "e" "l" "l" "o") empty) "hello")
(check-expect (decoder (list "a") (list "keep")) "a")
(check-expect (decoder (list "a") (list "space")) " ")
(check-expect (decoder (list "a") (list "remove")) "")
(check-expect (decoder (list "i" "m" "h" "l" "o" "y"
"v" "u" "e" "l" "y" "h" "o" "u")
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller skye3. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for CA$12.58. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
53068 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now