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From: HenHanna <HenHanna@devnull.tb>
Newsgroups: rec.puzzles,comp.lang.lisp,sci.lang,sci.math
Subject: Re: The "Strand" puzzle --- ( Continued Fractions using Lisp
 orPython? )
Date: Thu, 1 Aug 2024 12:47:30 -0700
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On 8/1/2024 2:33 AM, B. Pym wrote:
> HenHanna wrote:
> 
>>>> e.g. -------- For the (street)  Numbers (1,2,3,4,5,6,7,8)
>>>>
>>>>         (1,2,3,4,5)  and  (7,8)  both add up to 15.
>>>>
>>>>
>>>>
>>>> "In a given street of houses with consecutive numbers between
>>>> 50 and 500, find the house number, for which, the sum of
>>>> numbers on the left is equal to the sum of numbers on the
>>>> right"

> 
> Gauche Scheme
> 
> (define (strand lst)
>    (let go ((left-sum 0) (tail lst))
>      (if (null? tail)
>        #f
>        (let ((right-sum (fold + 0 (cdr tail))))
>          (cond ((< left-sum right-sum)
>                 (go (+ left-sum (car tail)) (cdr tail)))
>                ((= left-sum right-sum) (car tail))
>                (#t #f))))))
> 
> (strand '(1 2 3 4 5 6 7 8))
>    ===>
> 6
> 
> (lrange 2 5)
>    ===>
> (2 3 4)
> 
> (any
>    (lambda (n)
>      (if (strand (lrange 50 n))
>        n
>        #f))
>    (lrange 500 50 -1))
>    ===>
> 352
> 
> (strand (lrange 50 352))
>    ===>
> 251


               does your Newsreader  set  Followup-to   automatically?
                        pls  disable it.




i still don't see how the prob is related to the Continued  Fraction.



if this Continued  Fraction  is written as  [2,1]  with a bar over 1 (?)

                                 What does   [3,1]  correspond to?