main :: IO()
main = do
    print $ "Hello world"

dominates f g xs = and [abs (f x) >= abs (g x) | x <- xs]

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

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

listOfIndexes1 :: Int -> [Int] -> [Int]
listOfIndexes1 n xs = [ index | (x, index) <- zip xs [0..], x == n]

findNb :: Integer -> Integer
findNb m = helper 1 2
    where
        helper :: Integer -> Integer -> Integer
        helper cSum toAdd
            | cSum > m = -1
            | cSum == m = toAdd - 1
            | otherwise = helper (cSum + toAdd*toAdd*toAdd) (toAdd+1)

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

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

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

getIndices xs = (\x -> head [(pos1, pos2) | (x1, pos1) <- zip xs [0..], (x2, pos2) <- zip xs [0..], x = x1 + x2 && pos1 /= pos2])

poly xs = (\x -> sum [n * (x^i) | (n, i) <- zip xs [0..length xs]])