gistfile1.txt

delete :: Ord k => k -> Map k a -> Map k a
delete = go
  where
    go :: Ord k => k -> Map k a -> Map k a
    go _ Tip = Tip
    go k (Bin _ kx x l r) =
        case compare k kx of
            LT -> balanceR kx x (go k l) r
            GT -> balanceL kx x l (go k r)
            EQ -> glue l r