;;lastbiggerthanfirst?: lon --> boolean
;; returns true if the last element is bigger than the first
;; returns false if list is empty.
(define (lastbiggerthanfirst lon)
  (cond
    [(empty? lon) false]
    [(cons? lon) (lbtf_helper (rest lon (first lon) (first lon)))]))

;;lbtf_helper: lon num num --> boolean
;; returns true if frst is smaller than the last element of lon.
;; lst is the last element so far.
(define (lbtf_helper lon frst lst)
  (cond
    [(empty? lon) (< frst lst)]
    [(cons? lon) (lbtf_helper (rest lon) frst (first lon))]))