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Problem 8 » 履歴 » バージョン 2

Noppi, 2023/12/27 01:51

1 1 Noppi 
[ホーム](https://redmine.noppi.jp) - [[Wiki|Project Euler]]
2 
# [[Problem 8]]
3 





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```scheme





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#!r6rs





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#!chezscheme





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(import (chezscheme))





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(define Problem8-number-string





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  (string-append "73167176531330624919225119674426574742355349194934"





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                 "96983520312774506326239578318016984801869478851843"





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                 "85861560789112949495459501737958331952853208805511"





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                 "12540698747158523863050715693290963295227443043557"





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                 "66896648950445244523161731856403098711121722383113"





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                 "62229893423380308135336276614282806444486645238749"





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                 "30358907296290491560440772390713810515859307960866"





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                 "70172427121883998797908792274921901699720888093776"





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                 "65727333001053367881220235421809751254540594752243"





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                 "52584907711670556013604839586446706324415722155397"





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                 "53697817977846174064955149290862569321978468622482"





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                 "83972241375657056057490261407972968652414535100474"





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                 "82166370484403199890008895243450658541227588666881"





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                 "16427171479924442928230863465674813919123162824586"





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                 "17866458359124566529476545682848912883142607690042"





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                 "24219022671055626321111109370544217506941658960408"





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                 "07198403850962455444362981230987879927244284909188"





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                 "84580156166097919133875499200524063689912560717606"





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                 "05886116467109405077541002256983155200055935729725"





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                 "71636269561882670428252483600823257530420752963450"))





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(define answer-8





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    2
    Noppi
    
  (let ((count (- (string-length Problem8-number-string) 13)))





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    1
    Noppi
    
    (let loop ((index 0) (max-num 0))





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      (if (< count index)





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        max-num





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        (let* ((sub-num (substring Problem8-number-string index (+ index 13)))





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               (char-lis (string->list sub-num))





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               (num-lis (map





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                          (lambda (char)





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                            (- (char->integer char)





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                               (char->integer #\0)))





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                          char-lis))





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               (product-num (fold-left * 1 num-lis)))





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          (loop (add1 index) (max max-num product-num)))))))





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(printf "8: ~D~%" answer-8)





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```