Clean : Project Euler 120 - 129

127

module main
import StdEnv, StdLib, BigInt

fact :: (Int -> [Int])
fact = f [2:[3,5..]] where
    f [x:xs] n
    	| n == 1        = []
        | x*x > n       = [n]
        | n rem x == 0  = [x:f [x:xs] (n/x)]
        | otherwise     = f xs n

rad :: (Int -> Int)
rad = prod o map hd o group o fact

Max :== 119999

radArr :: {#Int}
radArr =: {createArray (Max+1) 0 & [x] = rad x \\ x <- [1..Max]}

rs :: [Int]
rs =: sortBy (\x y = radArr.[x] < radArr.[y]) [1..Max]

as :: Int -> [Int]
as c = (filter (\a = c - a > a) o takeWhile (\a = c / radArr.[c] > radArr.[a] * 2)) rs

cs :: [Int]
cs =: [x \\ x <- [1..Max] | x > radArr.[x]]

Start = (toString o sum) [sum (f c (as c)) \\ c <- cs] where
    f c as = [toBigInt c \\ a <- as & c <- repeat c | hit a (c-a) c]
    hit a b c = ra * rb * rc <% c && gcd a b == 1 && gcd b c == 1 && gcd c a == 1 where
        ra = toBigInt radArr.[a]
        rb = toBigInt radArr.[b]
        rc = toBigInt radArr.[c]