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#| BEGIN (Write your solution here) |#
(define (f n)
(if (< n 3)
n
(+ (f (- n 1))
(* 2 (f (- n 2)))
(* 3 (f (- n 3))))))
(define (f-iter n)
(helper 0 1 2 n))
(define (helper a b c count)
(if (= count 0)
a
(helper b c (+ c (* 2 b) (* 3 a)) (- count 1))))
#| END |#
#| BEGIN (Write your solution here) |#
(define (f n)
(if (< n 3)
n
(+ (f (- n 1))
(* 2 (f (- n 2)))
(* 3 (f (- n 3))))))
(define (f-iter n)
(define (iter-step a b c count)
(if (= count 0)
a
(iter-step b c (+ c (* 2 b) (* 3 a)) (- count 1))))
(iter-step 0 1 2 n))
#| END |#
#| BEGIN (Write your solution here) |#
(define (f n)
(if (< n 3)
n
(+ (f (- n 1))
(* 2 (f (- n 2)))
(* 3 (f (- n 3))))))
(define (f-iter n)
(define (iter-step a b c count)
(if (= count 0)
c
(iter-step (+ a (* 2 b) (* 3 c)) a b (- count 1))))
(iter-step 2 1 0 n))
#| END |#
#| BEGIN (Write your solution here) |#
(define (f n)
(if (< n 3)
n
(+ (f (- n 1))
(* 2 (f (- n 2)))
(* 3 (f (- n 3))))))
(define (f-iter n)
(helper 0 1 2 n))
(define (helper a b c count)
(if (= count 0)
a
(helper b c (+ c (* 2 b) (* 3 a)) (- count 1))))
#| END |#
#| BEGIN (Write your solution here) |#
(define (f n)
(if (< n 3)
n
(+ (f (- n 1))
(* 2 (f (- n 2)))
(* 3 (f (- n 3))))))
(define (f-iter n)
(define (iter-step a b c count)
(if (= count 0)
a
(iter-step b c (+ c (* 2 b) (* 3 a)) (- count 1))))
(iter-step 0 1 2 n))
#| END |#
#| BEGIN (Write your solution here) |#
(define (f n)
(if (< n 3)
n
(+ (f (- n 1))
(* 2 (f (- n 2)))
(* 3 (f (- n 3))))))
(define (f-iter n)
(define (iter-step a b c count)
(if (= count 0)
c
(iter-step (+ a (* 2 b) (* 3 c)) a b (- count 1))))
(iter-step 2 1 0 n))
#| END |#