27 lines
684 B
Text
27 lines
684 B
Text
(define (number->list num)
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(let loop ((num num) (lst #null))
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(if (zero? num)
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lst
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(loop (quotient num 10) (cons (remainder num 10) lst)))))
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(define (** x) (* x x))
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(define (happy? num)
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(let loop ((num num) (seen #null))
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(cond
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((= num 1) #true)
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((memv num seen) #false)
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(else
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(loop (apply + (map ** (number->list num)))
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(cons num seen))))))
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(display "happy numbers: ")
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(let loop ((n 1) (count 0))
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(unless (= count 8)
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(if (happy? n)
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then
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(display n) (display " ")
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(loop (+ n 1) (+ count 1))
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else
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(loop (+ n 1) count))))
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(print)
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