def fusion(self, tree_node, tree_fusion_node, left=True):
"""It performs fusion between adjacent nodes in order to resolve underflow conditions"""
# if left == True s is at left of w
w = tree_node
s = tree_fusion_node
u = w._parent
p_parent = w._list_parent._node._parent #if left else w._list_parent._node._parent
tree = RedBlackTreeMap()
p = tree.add(
p_parent.key()) # To obtain a position of a generic RBTree
if left:
w.tree().catenate(w._tree, p, left=False, T2=s._tree)
w.tree()._l.fusion(s._tree._l, right=True)
root = w.tree().root()
left = w.tree().left(root)
right = w.tree().right(root)
w.tree()._update_black_height(left if left is not None else right)
self.check_overflow(w)
else:
s.tree().catenate(s._tree, p, left=True, T2=w._tree)
s.tree()._l.fusion(w._tree._l, right=False)
root = s.tree().root()
left = s.tree().left(root)
right = s.tree().right(root)
s.tree()._update_black_height(left if left is not None else right)
self.check_overflow(s)
#s.tree().add(p_parent.key())
del (u.tree()[p.key()])
def test_catenate(self):
tree = self._T
p50 = tree.add(50)
p30 = tree.add(30)
p60 = tree.add(60)
p25 = tree.add(25)
p35 = tree.add(35)
tree2 = RedBlackTreeMap()
p20 = tree2.add(20)
tree3 = RedBlackTreeMap()
p10 = tree3.add(10)
p5 = tree3.add(5)
p15 = tree3.add(15)
l = [p50, p20, p60, p10, p30, p5, p15, p25, p35]
tree.catenate(tree, pivot=tree2.root(), T2=tree3)
for i, pos in enumerate(tree.breadthfirst()):
self.assertEqual(pos, l[i])
tree4 = RedBlackTreeMap()
p70 = tree4.add(70)
tree5 = RedBlackTreeMap()
p80 = tree5.add(80)
p75 = tree5.add(75)
p85 = tree5.add(85)
tree.catenate(tree, pivot=tree4.root(), T2=tree5, left=False)
l = [p50, p20, p70, p10, p30, p60, p80, p5, p15, p25, p35, p75, p85]
for i, pos in enumerate(tree.breadthfirst()):
self.assertEqual(pos, l[i])
print(pos.key(), " = ", l[i].key())
def split(self, tree_node):
"""It splits the external B-Tree node, recalling the same internal operation"""
p = tree_node.tree()._get_median()
#split operation, called on internal BSTs, returns the obtained subtrees
if tree_node._parent is None:
T1, T2 = tree_node.tree().split(p)
else:
T1, T2 = tree_node.tree().split(p)
#parent = tree_node._parent
#tree_node._parent = tree_node
#Creo un nuovo albero
node_left = self.Node(T1)
node_right = self.Node(T2)
if tree_node._parent is None: #Sono la radice
tree_parent = RedBlackTreeMap()
np = tree_parent.add(p.key())
node_parent = self.Node(tree_parent)
self._root = node_parent
tree_node._parent = tree_node
#parent-children references settings
np._node._left_out._node._child = node_left
node_left._parent = node_parent
node_left._list_parent = np._node._left_out
self._update_children(node_left)
#parent-children references settings
np._node._right_out._node._child = node_right
node_right._parent = node_parent
node_right._list_parent = np._node._right_out
self._update_children(node_right)
self._num_node += 2
#parent._child = node_parent
else:
node_parent = tree_node._parent
new_p = node_parent.tree().add(p.key())
#parent-children references settings
new_p._node._left_out._node._child = node_left
node_left._parent = node_parent
node_left._list_parent = new_p._node._left_out
self._update_children(node_left)
#parent-children references settings
new_p._node._right_out._node._child = node_right
node_right._parent = node_parent
node_right._list_parent = new_p._node._right_out
self._update_children(node_right)
self._num_node += 1
self.check_overflow(node_parent)