Haskell Cartesian Product Recursively -

Haskell Cartesian Product Recursively -

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cartesian product 9 answers

i know how utilize list comprehension this, how can implement function recursively compute cartesian product given 2 sets?

here's i'm stuck (and i'm noob)

crossprod :: [int] -> [int] -> [(int,int)] crossprod xs ys | xs == [] || ys == [] = [] | otherwise = (head xs, head ys) : crossprod (tail xs) (ys)

the output of gives me

[(1,4),(1,5),(1,6)]

if sets [1,2,3] , [4,5,6] respectively.. how go getting rest?

i know guard, , if else please bare me.

the basic case this:

{-crossprodaux :: int -> [int] -> [(int,int)]-} crossprodaux x [] = [] crossprodaux x (a:b) = (x, a):(crossprodaux x b) {-crossprod :: [int] -> [int] -> [(int,int)]-} crossprod [] ys = [] crossprod (a:b) ys= (crossprodaux ys)++(crossprod b ys)

haskell cartesian-product