feat(rb): add mockup
Signed-off-by: Matej Focko <mfocko@redhat.com>
This commit is contained in:
parent
3bba030d53
commit
02ce49c86e
GPG key ID:
7C47D46246790496
2 changed files with 195 additions and 4 deletions
192
rbt.py
Normal file
192
rbt.py
Normal file
|
|
@ -0,0 +1,192 @@
|
|||
from node import Node, Comparable, RotateFunction
|
||||
from ranked_tree import RankedTree
|
||||
|
||||
import enum
|
||||
import logging
|
||||
from typing import Callable, Tuple, TypeVar, Optional
|
||||
|
||||
logger = logging.getLogger(__name__)
|
||||
T = TypeVar("T", bound=Comparable)
|
||||
|
||||
|
||||
class Colour(enum.IntEnum):
|
||||
Red = 0
|
||||
Black = 1
|
||||
|
||||
|
||||
def colour(x: Optional[Node[T]]) -> Colour:
|
||||
if not x or not x.parent:
|
||||
return Colour.Black
|
||||
|
||||
diff = Node.difference(x)
|
||||
assert diff in (0, 1)
|
||||
|
||||
return Colour(diff)
|
||||
|
||||
|
||||
class RBTree(RankedTree[T]):
|
||||
def is_correct_node(
|
||||
self, node: Optional[Node[T]], recursive: bool = True
|
||||
) -> bool:
|
||||
if not node:
|
||||
return True
|
||||
|
||||
left, right = Node.differences(node)
|
||||
if left not in (Colour.Red, Colour.Black):
|
||||
# left subtree has invalid difference
|
||||
return False
|
||||
elif right not in (Colour.Red, Colour.Black):
|
||||
# right subtree has invalid difference
|
||||
return False
|
||||
|
||||
if Node.difference(node) == Colour.Red and (
|
||||
left == Colour.Red or right == Colour.Red
|
||||
):
|
||||
# two consecutive red nodes
|
||||
return False
|
||||
|
||||
return not recursive or (
|
||||
self.is_correct_node(node.left)
|
||||
and self.is_correct_node(node.right)
|
||||
)
|
||||
|
||||
# region InsertRebalance
|
||||
|
||||
def _insert_rebalance_step(
|
||||
self,
|
||||
x: Node[T],
|
||||
d: Optional[Node[T]],
|
||||
y: Node[T],
|
||||
rotate_left: RotateFunction,
|
||||
rotate_right: RotateFunction,
|
||||
) -> Node[T]:
|
||||
p = x.parent
|
||||
pp = p.parent
|
||||
|
||||
if d is not None and colour(d) == Colour.Red:
|
||||
pp.rank += 1
|
||||
x = pp
|
||||
elif x == y:
|
||||
x = p
|
||||
rotate_left(tree=self, x=p)
|
||||
else:
|
||||
rotate_right(tree=self, x=pp)
|
||||
|
||||
return x
|
||||
|
||||
def _insert_rebalance(self, x: Node[T]) -> None:
|
||||
while x.parent is not None and colour(x.parent) == Colour.Red:
|
||||
p = x.parent
|
||||
pp = x.parent.parent
|
||||
|
||||
assert pp
|
||||
if p == pp.left:
|
||||
x = self._insert_rebalance_step(
|
||||
x, pp.right, p.right, Node.rotate_left, Node.rotate_right
|
||||
)
|
||||
else:
|
||||
x = self._insert_rebalance_step(
|
||||
x, pp.left, p.left, Node.rotate_right, Node.rotate_left
|
||||
)
|
||||
|
||||
# endregion InsertRebalance
|
||||
|
||||
# region DeleteRebalance
|
||||
|
||||
def _delete_rebalance_step(
|
||||
self,
|
||||
x: Node[T],
|
||||
w: Node[T],
|
||||
parent: Node[T],
|
||||
left: Callable[[Node[T]], Node[T]],
|
||||
right: Callable[[Node[T]], Node[T]],
|
||||
rotate_left: RotateFunction,
|
||||
rotate_right: RotateFunction,
|
||||
) -> Tuple[Optional[Node[T]], Optional[Node[T]]]:
|
||||
if colour(w) == Colour.Red:
|
||||
logger.debug("RB-Delete: Case 1 -- x's sibling w is red")
|
||||
# w.colour = Colour.Black
|
||||
# x.parent.colour = Colour.Red
|
||||
rotate_left(tree=self, x=parent)
|
||||
w = right(parent)
|
||||
|
||||
if colour(w.left) == Colour.Black and colour(w.right) == Colour.Black:
|
||||
logger.debug(
|
||||
"RB-Delete: Case 2 -- x's sibling w is black, and both of w's children are black"
|
||||
)
|
||||
# w.colour = Colour.Red
|
||||
parent.rank -= 1
|
||||
x = parent
|
||||
else:
|
||||
if colour(right(w)) == Colour.Black:
|
||||
logger.debug(
|
||||
"RB-Delete: Case 3 -- x's sibling w is black, w's left child is red, and w's right child is black"
|
||||
)
|
||||
# left(w).colour = Colour.Black
|
||||
# w.colour = Colour.Red
|
||||
rotate_right(tree=self, x=w)
|
||||
w = right(parent)
|
||||
logger.debug(
|
||||
"RB-Delete: Case 4 -- x's sibling w is black, and w's right child is red"
|
||||
)
|
||||
# w.colour = colour(x.parent)
|
||||
# x.parent.colour = Colour.Black
|
||||
# right(w).colour = Colour.Black
|
||||
rotate_left(tree=self, x=parent)
|
||||
x = self.root
|
||||
|
||||
return x, (x.parent if x else None)
|
||||
|
||||
def _delete_rebalance(
|
||||
self, node: Optional[Node[T]], parent: Optional[Node[T]]
|
||||
) -> None:
|
||||
if not node and not parent:
|
||||
return
|
||||
|
||||
logger.debug(
|
||||
"RB-Delete: Called with node=‹%s› parent=‹%s›", node, parent
|
||||
)
|
||||
logger.debug("RB-Delete: Colour of node: %s", colour(node))
|
||||
if (node and 2 not in Node.differences(node)) or (
|
||||
2 not in Node.differences(parent)
|
||||
):
|
||||
# we haven't deleted a black node
|
||||
logger.debug(
|
||||
"RB-Delete: No black node has been deleted; node: %s; diffs: %s",
|
||||
node,
|
||||
Node.differences(node),
|
||||
)
|
||||
return
|
||||
|
||||
logger.debug("RB-Delete: Tree before rebalancing:\n%s", str(self))
|
||||
|
||||
while node != self.root and colour(node) == Colour.Black:
|
||||
logger.debug(
|
||||
"RB-Delete: Rebalancing node=‹%s› (%s-node) parent=‹%s› (%s-node)",
|
||||
node,
|
||||
Node.differences(node),
|
||||
parent,
|
||||
Node.differences(parent),
|
||||
)
|
||||
if node == parent.left:
|
||||
node, parent = self._delete_rebalance_step(
|
||||
node,
|
||||
parent.right,
|
||||
parent,
|
||||
lambda x: x.left,
|
||||
lambda x: x.right,
|
||||
Node.rotate_left,
|
||||
Node.rotate_right,
|
||||
)
|
||||
else:
|
||||
node, parent = self._delete_rebalance_step(
|
||||
node,
|
||||
parent.left,
|
||||
parent,
|
||||
lambda x: x.right,
|
||||
lambda x: x.left,
|
||||
Node.rotate_right,
|
||||
Node.rotate_left,
|
||||
)
|
||||
|
||||
# endregion DeleteRebalance
|
||||
|
|
@ -1,6 +1,7 @@
|
|||
from avl import AVLTree
|
||||
from wavl import WAVLTree
|
||||
from ravl import RAVLTree
|
||||
from rbt import RBTree
|
||||
|
||||
import logging
|
||||
import random
|
||||
|
|
@ -13,8 +14,7 @@ logger = logging.getLogger(__name__)
|
|||
|
||||
|
||||
@pytest.mark.parametrize(
|
||||
("RankBalancedTree"),
|
||||
[AVLTree, WAVLTree, RAVLTree]
|
||||
("RankBalancedTree"), [RBTree, AVLTree, WAVLTree, RAVLTree]
|
||||
)
|
||||
@hypothesis.settings(max_examples=10000)
|
||||
@hypothesis.given(values=st.sets(st.integers()))
|
||||
|
|
@ -44,8 +44,7 @@ def _report(t_before: str, t_after: str) -> None:
|
|||
|
||||
|
||||
@pytest.mark.parametrize(
|
||||
("RankBalancedTree"),
|
||||
[AVLTree, WAVLTree, RAVLTree]
|
||||
("RankBalancedTree"), [RBTree, AVLTree, WAVLTree, RAVLTree]
|
||||
)
|
||||
@hypothesis.settings(max_examples=10000)
|
||||
@hypothesis.given(config=delete_strategy())
|
||||
|
|
|
|||
Loading…
Reference in a new issue