Re: [Bug-apl] Best way to solve my daughter's maths problem

[enztec]

since no one has responded yet this is my best guess without pure random code 
testing from array of chars following your rules

the answer is :  ⍎'(((4+4)x4)-4)÷4'     ;)
i think the problem is from an episode of cartalk ??



On Tue, 24 Jan 2017 23:47:10 +0800
Elias Mårtenson <address@hidden> wrote:

> My daughter had this maths problem, and quote it from memory:
> 
> Given five 4's, separated by the mathematical functions +, -, × and ÷ form
> the number 7. The problem also allowed her to use parentheses.
> 
> I decided to write an APL expression to solve this, and this is what I came
> up with:
> 
> 
> *    d ← {⍵÷⍺}*
> *    (↑¨ 7 = ⍎¨ v) / v ← {"4 " , ↑,/ {{⍵," 4 "}¨⍵} ⍵}¨ ,↑∘.,/4 ⍴ ⊂'+-×d'*
> 
> Now, this program finds two solutions, which is good enough for me.
> However, my program doesn't find solutions that require parentheses.
> 
> Problem 1: Can anyone simplify my program?
> Problem 2: Can anyone come up with a solution that also checks for
> parentheses?
> 
> Regards,
> Elias