Scheme function to duplicate every element of a list a specified number of times











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This code takes a list and a integer and duplicates every element in the list the specified number of times.



(define (super-duper source count)
(define (next-super source left)
(if (zero? left)
(super-duper (cdr source) count)
(cons (super-duper (car source) count) (next-super source (- left 1)))))

(if (pair? source)
(cons (super-duper (car source) count) (next-super source (- count 1)))
source))

(display(super-duper '((x y) t) 3))









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    up vote
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    down vote

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    This code takes a list and a integer and duplicates every element in the list the specified number of times.



    (define (super-duper source count)
    (define (next-super source left)
    (if (zero? left)
    (super-duper (cdr source) count)
    (cons (super-duper (car source) count) (next-super source (- left 1)))))

    (if (pair? source)
    (cons (super-duper (car source) count) (next-super source (- count 1)))
    source))

    (display(super-duper '((x y) t) 3))









    share|improve this question


























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      This code takes a list and a integer and duplicates every element in the list the specified number of times.



      (define (super-duper source count)
      (define (next-super source left)
      (if (zero? left)
      (super-duper (cdr source) count)
      (cons (super-duper (car source) count) (next-super source (- left 1)))))

      (if (pair? source)
      (cons (super-duper (car source) count) (next-super source (- count 1)))
      source))

      (display(super-duper '((x y) t) 3))









      share|improve this question















      This code takes a list and a integer and duplicates every element in the list the specified number of times.



      (define (super-duper source count)
      (define (next-super source left)
      (if (zero? left)
      (super-duper (cdr source) count)
      (cons (super-duper (car source) count) (next-super source (- left 1)))))

      (if (pair? source)
      (cons (super-duper (car source) count) (next-super source (- count 1)))
      source))

      (display(super-duper '((x y) t) 3))






      recursion scheme






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      edited Sep 20 at 3:03









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      127k15148412










      asked Sep 20 at 0:09









      Dporth

      182




      182






















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          I think you need to decide weather to repeat only on the first level of the list, or if you want to do a tree walk for lists inside lists. As is, this code produces a weird combination of both in an exponential explosion of the list, The following sample returns over 2 million leaf elements for an input of length 26 and a repeat of 10.



          (leaf-count (super-duper '(a (b (c (d (e f g (h i) j k) l m n o) p q ) r (s t (u v) w ) x y) z) 10)) 
          ->> 2576420

          (define (leaf-count Tree)
          (cond ((null? Tree) 0)
          ((not (pair? Tree)) 1)
          (else (+ (leaf-count (car Tree))
          (leaf-count (cdr Tree))))))





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            I think you need to decide weather to repeat only on the first level of the list, or if you want to do a tree walk for lists inside lists. As is, this code produces a weird combination of both in an exponential explosion of the list, The following sample returns over 2 million leaf elements for an input of length 26 and a repeat of 10.



            (leaf-count (super-duper '(a (b (c (d (e f g (h i) j k) l m n o) p q ) r (s t (u v) w ) x y) z) 10)) 
            ->> 2576420

            (define (leaf-count Tree)
            (cond ((null? Tree) 0)
            ((not (pair? Tree)) 1)
            (else (+ (leaf-count (car Tree))
            (leaf-count (cdr Tree))))))





            share|improve this answer

























              up vote
              0
              down vote













              I think you need to decide weather to repeat only on the first level of the list, or if you want to do a tree walk for lists inside lists. As is, this code produces a weird combination of both in an exponential explosion of the list, The following sample returns over 2 million leaf elements for an input of length 26 and a repeat of 10.



              (leaf-count (super-duper '(a (b (c (d (e f g (h i) j k) l m n o) p q ) r (s t (u v) w ) x y) z) 10)) 
              ->> 2576420

              (define (leaf-count Tree)
              (cond ((null? Tree) 0)
              ((not (pair? Tree)) 1)
              (else (+ (leaf-count (car Tree))
              (leaf-count (cdr Tree))))))





              share|improve this answer























                up vote
                0
                down vote










                up vote
                0
                down vote









                I think you need to decide weather to repeat only on the first level of the list, or if you want to do a tree walk for lists inside lists. As is, this code produces a weird combination of both in an exponential explosion of the list, The following sample returns over 2 million leaf elements for an input of length 26 and a repeat of 10.



                (leaf-count (super-duper '(a (b (c (d (e f g (h i) j k) l m n o) p q ) r (s t (u v) w ) x y) z) 10)) 
                ->> 2576420

                (define (leaf-count Tree)
                (cond ((null? Tree) 0)
                ((not (pair? Tree)) 1)
                (else (+ (leaf-count (car Tree))
                (leaf-count (cdr Tree))))))





                share|improve this answer












                I think you need to decide weather to repeat only on the first level of the list, or if you want to do a tree walk for lists inside lists. As is, this code produces a weird combination of both in an exponential explosion of the list, The following sample returns over 2 million leaf elements for an input of length 26 and a repeat of 10.



                (leaf-count (super-duper '(a (b (c (d (e f g (h i) j k) l m n o) p q ) r (s t (u v) w ) x y) z) 10)) 
                ->> 2576420

                (define (leaf-count Tree)
                (cond ((null? Tree) 0)
                ((not (pair? Tree)) 1)
                (else (+ (leaf-count (car Tree))
                (leaf-count (cdr Tree))))))






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                share|improve this answer










                answered Sep 25 at 4:06









                WorBlux

                35116




                35116






























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