Sorry, my line breaks got deleted in the email. Her is my Python code:
def pe85(larg, rarg): count = 0
llist = range(1, larg+1)
rlist = range(1, rarg+1)
for l in llist:
for r in rlist:
count += l*r
return count
if __name__ == "__main__":
# test for 2x3 grid, as in question.
k = pe85(2,3)
print str(k)
l1 = range(1,200)
l2 = range(1,200)
bestfit = 10000
area = 0
for i in l1:
for j in l2:
diff = abs(2000000 - pe85(i,j))
if diff < bestfit:
area = i*j
bestfit = diff
print "AREA is "+str(area)
> From: [email protected]
> To: [email protected]
> Date: Tue, 7 Oct 2014 05:37:27 +0100
> Subject: [Jprogramming] Project Euler 85, Python and J
>
> Project Euler 85: https://projecteuler.net/problem=85
> This problem is not really conceptually hard, but I am struggling with a J
> solution.I have solved it in Python:
> =============================================
> def pe85(larg, rarg): count = 0 llist = range(1, larg+1) rlist =
> range(1, rarg+1)
> for l in llist: for r in rlist: count += l*r
> return count
>
> if __name__ == "__main__": # test for 2x3 grid, as in question. k =
> pe85(2,3) print "Test value: "+str(k) l1 = range(1,200) # 200
> lucky guess l2 = range(1,200) bestfit = 10000 # just a big number
> area = 0 for i in l1: for j in l2:
> diff = abs(2000000 - pe85(i,j)) if diff < bestfit:
> area = i*j bestfit =
> diff
> print "AREA is "+str(area)
>
>
> ================================================The above script will give
> the final area of the closest fit to 2 million. (The python code may not be
> the best). Also I tested all possibilities up to 200x200, which was chosen
> arbitrarily(~ish).
> Next my J. I go the inner calculation ok (i.e. see the function pe85 above).
> In J I have:
> pe85 =: +/@:+/@:((>:@:i.@:[) *"(0 _) (>:@:i.@:]))
> NB. I know, too brackety. Any tips for improvement appreciated.
>
>
> But from here things get tricky. If I do the calculation over 200x200
> possibilities I end up with a big matrix, of which I have to find the closest
> value to 2 million, of which then I have to somehow get the (x,y) values of
> and then find the area by x*y.
>
> The main issue is getting the (x,y) from the best fit value of the array.
>
> i.e. If I do pe85"(0)/~ 200, I get a big array, and I know I can get the
> closest absolute value to 2 million but then I need to get the original
> values to multiply together to give the best fit area. Actually I have bumped
> into this issue many times. It is easy enough in a 1-d array,just do:
> (I. somefunc ) { ])
>
> or similar to get the index. But for two indices the problem is beyond me at
> the moment. Any help appreciated.Regards,Jon
>
>
>
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