main :: IO()
main = do
    print $ "Hello world"
    print $ "Let's go!"

dominaes ::
dominats f g xs = and [abs (f x) >= abs (g x) | x <- xs]

seriesSum :: Double -> Int -> Double
seriesSum n x = sum [s | i <- [1..n], s <- [x^i + fromIntegral (i^2) + 1]]

listToFunction ::
listToFunction lst = (\x -> [xi + 10 | xi <- lst, x == xi])

findNb :: Integer -> Integer
findNb m = helper m 1
    where
        helper :: Integer -> Integer -> Integer
        helper m i
            | m < i = -1
            | otherwise = helper (m - 1 ^ 3) (i+1)

iterator ::
iterator f xs = helper xs
    where
        helper :: [Int] -> Bool
        helper [] = True
        helper (x:xs)
            | null xs = True
            | head xs = f x = helper xs
            | otherwise = False

applyKth ::
applyKth p xs = (\k -> if length filtered > k then error "No such number" else filtered!!(k-1))
    where
        filtered = filter p xs

applyEveryKth ::
applyEveryKth f k xs = helper 1 xs
    where
        helper :: Int -> [Int] -> [Int]
        helper _ [] = []
        helper i (x:xs)
            | i == k = f x : helper 1 xs
            | otherwise = x : helper (i+1) xs

speak :: String -> (Char -> String)
speak str c = (\acc (pos, x) -> if x == c then acc ++ show pos else acc ++ [x]) [] $ zip str $ reverse [0 .. length str-1]