sicp 2.62

sicp_2_62

(define a '(1 2 4 6))
(define b '(3 4 5 6 7 8))

(define (union-set x y)
  (cond 
    ((null? x) y)
    ((null? y) x)
           ((= (car x) (car y))
         (cons (car x) (union-set (cdr x) (cdr y))))
        ((< (car x) (car y))
         (cons (car x) (union-set (cdr x) y)))
        (else (cons (car y) (union-set x (cdr y))))))


(union-set a b)