1.txt

#lang scheme/base

;------------------------------- a

(define (2n-1!-list-a n)
  (if (<= n 0)
      '()
      (let loop ((i 1) (result 1) (arr '()))
        (cond ( (and (<= i (+ n 1)) (even? i)) (loop (+ i 1) (* i result) (cons result arr)))
              ( (and (<= i (+ n 1)) (not(even? i))) (loop (+ i 1) (* i result) arr))
              (else (reverse arr))   
              )
        )
  )
)

;-------------------------------b

(define (factorial n)
  (if (= n 0)
      1
      (* n (factorial (- n 1)))
  )
)

(define (factlist n)
  (if (<= n 0)
      '()
      (cons (factorial n) (factlist(- n 2)))
  )
)

(define (2n-1!-list-b n)
  (if (even? n)
      (reverse (factlist(- n 1)))
      (reverse (factlist n))
  )
)

;-------------------------------

(define a 2n-1!-list-a)
(define b 2n-1!-list-b)