def insert(self, key):
#add a key to the tree. Don't forget to fix up the tree and balance the nodes.
#is there a root? if not, what do you have to do?
#if there is, how does that change things?
if self.root is None: #checks to see if the root is none, if not the new node will become the root
node = RB_Node(key)
self.root = node
node.parent = self.sentinel #sets parents and children to sentinel nodes
node.leftChild = self.sentinel
node.rightChild = self.sentinel
node.color = "black" #root node is always black
else:
node = RB_Node(key)
y = self.sentinel
x = self.root
while x != self.sentinel: #x is the root, will go down the tree until x reaches a sentinel node
y = x #keeps track of the parent node
if node.key < x.key: #determining which path x will take
x = x.leftChild
else:
x = x.rightChild
node.parent = y #sets the parent to y
if y == self.sentinel: #if y was a sentinel, the node must become the root since only
self.root = node #the root has a sentinel parent
elif node.key < y.key:
y.leftChild = node #determining if it's a left or right child
else:
y.rightChild = node
node.leftChild = self.sentinel #sets the children to sentinels
node.rightChild = self.sentinel
node.color = "red" #newly inserted nodes are red
self._rbInsertFixup(node)
def insert(self, key):
'''
Add a key to the tree. Don't forget to fix up the tree ad balance the nodes.
'''
# Create new node
z = RB_Node(key)
# Set y to be sentinel
y = self.sentinel
# Set x to be root
x = self.root
# If the root is none, set x to be sentinel
if (x == None):
x = self.sentinel
# While x is not the sentinel...
while (x != self.sentinel):
# Sentinel = root
y = x
# If z's key is greater than x's key...
if (z.key < x.key):
# Make x the left child
x = x.leftChild
else:
# Make x the right child
x = x.rightChild
# Make z's parent y
z.parent = y
# If y is equal to the sentinel...
if (y == self.sentinel):
# Set the root to be z
self.root = z
# If z's key is less than y's key...
elif (z.key < y.key):
# Set y's left child equal to z
y.leftChild = z
else:
# Else, set y's right child equal to z
y.rightChild = z
# Set z's left child to be sentinel
z.leftChild = self.sentinel
# Set z's right child to be sentinel
z.rightChild = self.sentinel
# Set z's color to be red
z.color = 'red'
# Call insert fixup
self._rbInsertFixup(z)
def insert(self, key):
"""
Add a key to the tree. Don't forget to fix up the tree and balance the nodes.
Insert always needs to search to the bottom of the tree to find where where
the new key (node z) should be.
You put z there and color it read to maintain the black-height, but then
you need to check if this causes a problem with two reds in a row, and
if this is the case, then we fix this issue by color shifting/rotation which
is seen later on.
"""
z = RB_Node(key) # creates node
y = self.sentinel # basically means null
x = self.root
if x is None:
x = self.sentinel
while x != self.sentinel:
y = x
if z.key < x.key:
x = x.leftChild
else:
x = x.rightChild
z.parent = y
if y == self.sentinel:
self.root = z
elif z.key < y.key:
y.leftChild = z
else:
y.rightChild = z
z.leftChild = self.sentinel
z.rightChild = self.sentinel
z.color = "Red"
self._rbInsertFixup(z)
def insert(self, key):
# add a key to the tree.Don't forget to fix up the tree and balance the nodes.
#root does not exist yet
y = self.sentinel
x = self.root
z = RB_Node(key, self.sentinel, self.sentinel, self.sentinel, 'red')
if x == None: #insert a node for root if the tree is empty
self.root = z
x = self.root
while x != self.sentinel: #move down the tree until hitting a sentinel node
y = x
if z.key < x.key:
x = x.leftChild
else:
x = x.rightChild
z.parent = y
if y == self.sentinel:
self.root = z # case for tree being empty
elif z.key < y.key:
y.leftChild = z #go left
#print key,
#print 'inserted as a left child of ',
#print y.key
else:
y.rightChild = z #go right
#print key,
#print ' inserted as a right child of',
#print y.key
z.leftChild = self.sentinel
z.rightChild = self.sentinel
z.color = 'red'
self.size += 1
self._rbInsertFixup(z)