write-ups-challenges-2021-2022/restrictive-racket/SOLUTION.md

Difficulty

• Free (5 punten)

How To Solve

(lambda (a) (+ a 1))

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IGCTF{CongratulationsYouAreSane!}

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Difficulty

• Easy (15 punten)

How To Solve

(begin (define (a b) (if (= b 0) #t (if (= b 1) #f (a (- b 2))))) a)

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IGCTF{FunThingsAreFun}

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Difficulty

• Somewhat easy (30 punten)

How To Solve

(begin (define (a b) (or (= b 0) (and (not (= b 1)) (a (- b 2))))) a)

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IGCTF{ICantThinkOfGoodFlags}

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Difficulty

• Average (50 punten)

How To Solve

This solution uses a Y combinator, for example this works: ((lambda (e d)
(e d))
(lambda (c)
((lambda (b) (b b))
(lambda (b) (c (lambda (a) ((b b) a)))))) (lambda (c)
(lambda (b)
(if (= b 0)
#t
(if (= b 1)
#f
(c (- b 2)))))))

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IGCTF{LambdasArePrettyAwesome}

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Difficulty

TODO

How To Solve

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