pyths :: Int->[(Int,Int,Int)]
pyths n = [(x,y,z)|x<-[1..n],y<-[1..n],z<-[1..n],x^2+y^2==z^2]

perfects :: Int->[Int]
perfects n = [x | x<-[1..n], (sum [y| y<-[1..x `div` 2], x `mod` y==0])==x]

scalar :: [Int]->[Int]->Int
scalar xs ys = sum [x*y|(x,y)<-(zip xs ys)]

quick :: [Int]->[Int]
quick [] = []
quick (x:xs) = (quick [y|y<-xs,y<=x]) ++ [x] ++ (quick [y|y<-xs, y>x])

and1 :: [Bool]->Bool
and1 [] = True
and1 (True:xs) = and1 xs
and1 (False:xs) = False