def _remove(self, node, key):
"""Remove (key,value) from subtree rooted at node and return resulting subtree."""
if node is None:
return None
if key < node.key:
node.left = self._remove(node.left, key)
node = resolve_right_leaning(node)
elif key > node.key:
node.right = self._remove(node.right, key)
node = resolve_left_leaning(node)
else:
if node.left is None:
return node.right
if node.right is None:
return node.left
# replace self value with largest value from left subtree
original = node
# find SMALLEST child in right subtree and remove it
node = node.right
while node.left:
node = node.left
node.right = self._remove_min(original.right)
node.left = original.left
node = resolve_left_leaning(node)
node.compute_height()
return node
def _remove(self, node, val):
"""Remove val from subtree rooted at node and return resulting subtree."""
if node is None:
return None
if val < node.value:
node.left = self._remove(node.left, val)
node = resolve_right_leaning(node)
elif val > node.value:
node.right = self._remove(node.right, val)
node = resolve_left_leaning(node)
else:
if node.left is None:
return node.right
if node.right is None:
return node.left
# replace self value with node containing smallest value from right subtree
original = node
# find SMALLEST child in right subtree and remove it
node = node.right
while node.left:
node = node.left
node.right = self._remove_min(original.right)
node.left = original.left
# Might have made left-leaning by shrinking right side
node = resolve_left_leaning(node)
node.compute_height()
return node
def _remove_max(self, node):
"""
Remove max and unwind, addressing AVL property on way back. Return
pair (value, new root)
"""
if node.right is None:
return (node.value, node.left)
(value, node.right) = self._remove_max(node.right)
node = resolve_left_leaning(node)
node.compute_height()
return (value, node)
def _insert(self, node, val):
"""Inserts a new BinaryNode to the tree containing this value."""
if node is None:
return BinaryNode(val)
if val <= node.value:
node.left = self._insert(node.left, val)
node = resolve_left_leaning(node)
else:
node.right = self._insert(node.right, val)
node = resolve_right_leaning(node)
node.compute_height()
return node
def _insert(self, node, v, p):
"""Inserts a new BinaryNode to the tree containing (value, priority) pair."""
if node is None:
return BinaryNode(v, p)
if p <= node.priority:
node.left = self._insert(node.left, v, p)
node = resolve_left_leaning(node)
else:
node.right = self._insert(node.right, v, p)
node = resolve_right_leaning(node)
node.compute_height()
return node
def _put(self, node, k, v):
"""
Adds a new BinaryNode to the subtree rooted at node or update
association of (k, v).
"""
if node is None:
return BinaryNode(k,v)
if k == node.key:
node.value = v
return node
if k < node.key:
node.left = self._put(node.left, k, v)
node = resolve_left_leaning(node)
else:
node.right = self._put(node.right, k, v)
node = resolve_right_leaning(node)
node.compute_height()
return node