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;; make-ints: int -> list-of-ints
;; makes a list of ascending integers from 1 to n or empty if n = 0.
;; Examples:
(check-expect (make-ints 0) empty)
(check-expect (make-ints 1) (list 1))
(check-expect (make-ints 2) (list 1 2))
(check-expect (make-ints 3) (list 1 2 3))

(define (make-ints n)
  (cond
    [(zero? n) empty]
    [(positive? n)
     (local
       [(define (helper acc i)
          (cond
            [(zero? i) acc]
            [(positive? i) (helper (cons i acc) (sub1 i))]))]
       (helper (list n) (sub1 n)))]))


(define ints (make-ints 1000000))  ;; reduce this value if you run out of memory intially.

;;max: num num --> num
;; returns the larger of the two numbers.

;; The following functions both return the largest value in the given list of positive numbers
(time (foldr max 0 ints))  ;; try increasing the size of ints above by factors of 10 until you run out of memory.
(time (foldl max 0 ints))  ;; comment out the foldr line and see if you still run out of memory.