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Ingy döt Net 2023-07-01 11:58:00 -04:00
parent 7387c8f97b
commit cb5bb5e222
199093 changed files with 3378972 additions and 0 deletions
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28
Task/Hailstone-sequence/Scheme/hailstone-sequence.ss Normal file
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(define (collatz n)
(if (= n 1) '(1)
(cons n (collatz (if (even? n) (/ n 2) (+ 1 (* 3 n)))))))
(define (collatz-length n)
(let aux ((n n) (r 1)) (if (= n 1) r
(aux (if (even? n) (/ n 2) (+ 1 (* 3 n))) (+ r 1)))))
(define (collatz-max a b)
(let aux ((i a) (j 0) (k 0))
(if (> i b) (list j k)
(let ((h (collatz-length i)))
(if (> h k) (aux (+ i 1) i h) (aux (+ i 1) j k))))))
(collatz 27)
; (27 82 41 124 62 31 94 47 142 71 214 107 322 161 484 242 121 364 182
; 91 274 137 412 206 103 310 155 466 233 700 350 175 526 263 790 395
; 1186 593 1780 890 445 1336 668 334 167 502 251 754 377 1132 566 283
; 850 425 1276 638 319 958 479 1438 719 2158 1079 3238 1619 4858 2429
; 7288 3644 1822 911 2734 1367 4102 2051 6154 3077 9232 4616 2308 1154
; 577 1732 866 433 1300 650 325 976 488 244 122 61 184 92 46 23 70 35
; 106 53 160 80 40 20 10 5 16 8 4 2 1)
(collatz-length 27)
; 112
(collatz-max 1 100000)
; (77031 351)