Bubble sort

checkFlag :: Ord a => [a] -> Int -> Bool -> [a]
checkFlag l i f =
  if f
    then check l i False
    else l

check :: Ord a => [a] -> Int -> Bool -> [a]
check l i f =
  if l !! i > l !! (i + 1)
    then swap l i
    else checkEnd l i f

swap :: Ord a => [a] -> Int -> [a]
swap l i =
  checkEnd (take i l ++ [l !! (i + 1)] ++ [l !! i] ++ drop (i + 2) l) i True

checkEnd :: Ord a => [a] -> Int -> Bool -> [a]
checkEnd l i f =
  if (i + 2) == length l
    then checkFlag l 0 f
    else check l (i + 1) f

main :: IO ()
main = print $ checkFlag [500,499 .. 0] 0 True

-- real 0m7,509s
-- user 0m7,468s
-- sys  0m0,013s