1 (require (planet "memoize.ss" ("dherman" "memoize.plt" 2 1)))
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3 (define/memo (collatz n)
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5 ((even? n) (add1 (collatz (/ n 2))))
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6 (else (add1 (collatz (add1 (* 3 n)))))))
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8 (let ((m -1) (the-number #f))
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11 (when (> (collatz n) m)
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12 (set! m (collatz n))
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13 (set! the-number n))
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