You can always write it like this:
listPairs = [ (x,y) | x <- [6 .. 499] , y <- [0 .. 1000] , isProduct x ,
isSqrt y , mod y x == 0 ]
So you have the bounds for x and y, and then the conditions. You then need
to define isProduct and isSqrt with types
isProduct :: Int -> Bool
isSqrt :: Int -> Bool
Hopefully, these problems will look easier separately.
Well, it's just an idea.
Good luck,
Daniel Díaz.
On Tue, May 14, 2013 at 4:57 PM, John
Hi,
I have to write a function which returns a list of all pairs (x,y) where x, y ∈ N AND: – x is the product of two natural numbers (x = a · b, where a, b ∈ N) AND – x is really bigger than 5 but really smaller than 500, AND – y is a squer number (y = c² where c ∈ N) NOT greater than 1000, AND – x is a divisor of y.
My attempt is as follows:
listPairs :: [(Int, Int)] listPairs = [(x,y) | x<-[0..], y<-[0..], x<-[0..]*[0..], x > 5, x < 500, (y*y) < 1001, mod y x == 0]
However it doesn't work unfortunatly
Could anyone tell me where my mistake is?
Thanks.
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