Any scheme master here?? some help plz ??

[TurtleMan]

Im writing two scheme , but i run into some problems.. im using Dr.Schme.. and im limited only to use use the following pre-defined Scheme procedures : define, lambda, cond (including the else notation), if, cons, car, cdr, null?, =, equal?, list?, odd?, and, or, not, +, -, *, /, <, <=, >, >=

And i can't figure out how to get this one ..

(calc-depth L) takes a list L and returns its depth. The depth of a list is defined as the maximum level of nesting of a list.

(calc-depth '( )) => 1
(calc-depth '(1 2 3)) => 1
(calc-depth '(1 (2) 3)) => 2
(calc-depth '(1 (2 (3) 4) 5)) => 3


and aslo this one ..

(deep-reverse L) takes a list L and returns the deep reversal of L. The deep reversal of L is a list R that contains all of the elements of L in reverse order. Further, for each element L' in L which is a list, the corresponding element in R is the "deep reversal" of L'.

(deep-reverse '( )) => ( )
(deep-reverse '(a b c)) => (c b a)
(deep-reverse '((a b c) d ((e f) g))) => ((g (f e)) d (c b a))

im totally lost and i tried so many different combo and it still doesn't work .. any help would be appricated ;]

 

[TurtleMan]

bump it up a bit :]

 

[z0mb13]

try this for the first one

(define (depth ls)
(cond ((null? ls) 1)
((list? (car ls)) (+ (depth (car ls)) (depth (cdr ls)))
(else
(depth (cdr ls)))))))))

my syntax may be a little of... but the idea is there, also I didnt count close parentheses

still working on the second one

EDIT: dammit the indentation is not correct

 

[z0mb13]

did that help??

 

[TurtleMan]

still figuring and trying test case =D thx !!

 

[TurtleMan]

you da bomb !!! it works


(define calc-depth
(lambda (L)
(cond
((null? L) 1)
((list? (car L)) (+ (calc-depth (car L)) (calc-depth (cdr L))))
(else (calc-depth (cdr L))))))


why is this the code so simple yet i was writing like mad lines of code and still get it !! recursive !!

 

[TurtleMan]

I was doing it, and the fourth case which is : (calc-depth '(1 (2 (3) 4) 5)) => 3
just totally throw me off , and yet that is how u suppose to do it !! 🙂

 

[TurtleMan]

im so exciting .. im refreshing this page like once every 30 sec !! 😀

 

[z0mb13]

eh u know that I was not online when u refreshed the page rite??

ok now Im working on the second one... too lazy yesterday

EDIT: the second one is recursive too

 

[z0mb13]

ok try this for the second one

(define (deep-reverse L)
(cond ((null? L) nil)
((null? (cdr L)) L)
((listp? (car L)) (list (deep-reverse (cdr L)) (deep-reverse (car L))))
(else (cons (deep-reverse (cdr L)) (car L)))))))


If the result is kinda funny (the parentheses are wrong) try playing with changing the list and the cons in line 4 and 5

 

[TurtleMan]

*Bowinng dow to z0mb13 *


you the best man !! I stuggle so bad on the deep-reverse ,
i even try to write a helper function it but still didn't work ...

you are my new idol now ^__^ thanks a lot !!!

 

[z0mb13]

scheme and lisp is powerful in that aspect: can do a lot of stuff with few line of code... and also it is recursive by nature (well maybe not.. but just the way I was taught at CAL)

EDIT: thanks for the praise.. I hope u doin well in the class!! 🙂

 

[TurtleMan]

:]

 

[TurtleMan]

Originally posted by: z0mb13
scheme and lisp is powerful in that aspect: can do a lot of stuff with few line of code... and also it is recursive by nature (well maybe not.. but just the way I was taught at CAL)

EDIT: thanks for the praise.. I hope u doin well in the class!! 🙂

lol i almost pass the class, i think bc i missed 1 schme probelm that's why i can't advance to the next class :]
thats why im here to check it out again !!

 

[SwervTek]

Let me guess....UCI ICS major? Class : ICS 23....i had to do that same exact problem...lol...<Goes back to check his old program>