[Solved] Write scheme LISP Atomic_Count [closed]

by


Not too hard, the main point is that you need some kind of buffer (called prev in my case) to wait for a possible multiplication:

(define (atomic_count lst)
  (let loop ((lst lst) (prev 0))
    (if (null? lst) 
        prev
        (let ((elt (car lst)))
          (cond
            ((list? elt)   (+ prev (loop (cdr lst) (loop elt 0))))
            ((number? elt) (loop (cdr lst) (* prev elt)))
            (else          (+ prev (loop (cdr lst) 1))))))))

Testing:

> (atomic_count '(c o 2 (h 2 o) 3 o 2))
14
> (atomic_count '(h 2 o))
3
> (atomic_count '(c o 2 o 2))
5

3

solved Write scheme LISP Atomic_Count [closed]