let rec move_botleft (z : 'a zipper) : 'a zipper =
(* returns z if the targetted node in z has no children *)
- (* else returns move_botleft (zipper which results from moving down and left in z) *)
+ (* else returns move_botleft (zipper which results from moving down from z to the leftmost child) *)
_____
(* YOU SUPPLY THE DEFINITION *)
(same-fringe? tree1 tree2)
-<!--
- (define (lazy-flatten tree)
- (letrec ([helper (lambda (tree tailk)
- (cond
- [(pair? tree)
- (helper (car tree) (lambda () (helper (cdr tree) tailk)))]
- [else (cons tree tailk)]))])
- (helper tree (lambda () (list)))))
-
- (define (stream-equal? stream1 stream2)
- (cond
- [(and (null? stream1) (null? stream2)) #t]
- [(and (pair? stream1) (pair? stream2))
- (and (equal? (car stream1) (car stream2))
- (stream-equal? ((cdr stream1)) ((cdr stream2))))]
- [else #f]))
-
- (define (same-fringe? tree1 tree2)
- (stream-equal? (lazy-flatten tree1) (lazy-flatten tree2)))
-
- (define tree1 '(((1 . 2) . (3 . 4)) . (5 . 6)))
- (define tree2 '(1 . (((2 . 3) . (4 . 5)) . 6)))
-
- (same-fringe? tree1 tree2)
--->