def test_color_node():
c_node = ColorNode(1, color=Color.RED)
assert c_node.color == Color.RED
c_node.color = Color.BLACK
assert c_node.color == Color.BLACK
assert c_node.val == 1
assert c_node.left == None
assert c_node.right == None
def _flip_color(self, node: ColorNode) -> None:
"""
Flip the color of the node and its children.
"""
if node.color == Color.RED:
node.color = Color.BLACK
else:
node.color = Color.RED
if node.left.color == Color.RED:
node.left.color = Color.BLACK
else:
node.left.color = Color.RED
if node.right.color == Color.RED:
node.right.color = Color.BLACK
else:
node.right.color = Color.RED
def _rotate_right(self, node: ColorNode) -> ColorNode:
"""
The node's left child is red. Perform right-rotation to make the node's right child red.
"""
x = node.left
node.left = x.right
x.right = node
x.color = node.color
node.color = Color.RED
return x
def _rotate_left(self, node: ColorNode) -> ColorNode:
"""
The node's right child is red. Perform left-rotation to comply red-left-leaning rule.
"""
x = node.right
node.right = x.left
x.left = node
x.color = node.color
node.color = Color.RED
return x