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adds skip packaging option #161

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280 changes: 280 additions & 0 deletions Trees/RedBlackTree.py
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Original file line number Diff line number Diff line change
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class Node():
def __init__(self,val):
self.val = val # Value of Node
self.parent = None # Parent of Node
self.left = None # Left Child of Node
self.right = None # Right Child of Node
self.color = 1 # Red Node as new node is always inserted as Red Node

# Define R-B Tree
class RBTree():
def __init__(self):
self.NULL = Node ( 0 )
self.NULL.color = 0
self.NULL.left = None
self.NULL.right = None
self.root = self.NULL


# Insert New Node
def insertNode(self, key):
node = Node(key)
node.parent = None
node.val = key
node.left = self.NULL
node.right = self.NULL
node.color = 1 # Set root colour as Red

y = None
x = self.root

while x != self.NULL : # Find position for new node
y = x
if node.val < x.val :
x = x.left
else :
x = x.right

node.parent = y # Set parent of Node as y
if y == None : # If parent i.e, is none then it is root node
self.root = node
elif node.val < y.val : # Check if it is right Node or Left Node by checking the value
y.left = node
else :
y.right = node

if node.parent == None : # Root node is always Black
node.color = 0
return

if node.parent.parent == None : # If parent of node is Root Node
return

self.fixInsert ( node ) # Else call for Fix Up


def minimum(self, node):
while node.left != self.NULL:
node = node.left
return node


# Code for left rotate
def LR ( self , x ) :
y = x.right # Y = Right child of x
x.right = y.left # Change right child of x to left child of y
if y.left != self.NULL :
y.left.parent = x

y.parent = x.parent # Change parent of y as parent of x
if x.parent == None : # If parent of x == None ie. root node
self.root = y # Set y as root
elif x == x.parent.left :
x.parent.left = y
else :
x.parent.right = y
y.left = x
x.parent = y


# Code for right rotate
def RR ( self , x ) :
y = x.left # Y = Left child of x
x.left = y.right # Change left child of x to right child of y
if y.right != self.NULL :
y.right.parent = x

y.parent = x.parent # Change parent of y as parent of x
if x.parent == None : # If x is root node
self.root = y # Set y as root
elif x == x.parent.right :
x.parent.right = y
else :
x.parent.left = y
y.right = x
x.parent = y


# Fix Up Insertion
def fixInsert(self, k):
while k.parent.color == 1: # While parent is red
if k.parent == k.parent.parent.right: # if parent is right child of its parent
u = k.parent.parent.left # Left child of grandparent
if u.color == 1: # if color of left child of grandparent i.e, uncle node is red
u.color = 0 # Set both children of grandparent node as black
k.parent.color = 0
k.parent.parent.color = 1 # Set grandparent node as Red
k = k.parent.parent # Repeat the algo with Parent node to check conflicts
else:
if k == k.parent.left: # If k is left child of it's parent
k = k.parent
self.RR(k) # Call for right rotation
k.parent.color = 0
k.parent.parent.color = 1
self.LR(k.parent.parent)
else: # if parent is left child of its parent
u = k.parent.parent.right # Right child of grandparent
if u.color == 1: # if color of right child of grandparent i.e, uncle node is red
u.color = 0 # Set color of childs as black
k.parent.color = 0
k.parent.parent.color = 1 # set color of grandparent as Red
k = k.parent.parent # Repeat algo on grandparent to remove conflicts
else:
if k == k.parent.right: # if k is right child of its parent
k = k.parent
self.LR(k) # Call left rotate on parent of k
k.parent.color = 0
k.parent.parent.color = 1
self.RR(k.parent.parent) # Call right rotate on grandparent
if k == self.root: # If k reaches root then break
break
self.root.color = 0 # Set color of root as black


# Function to fix issues after deletion
def fixDelete ( self , x ) :
while x != self.root and x.color == 0 : # Repeat until x reaches nodes and color of x is black
if x == x.parent.left : # If x is left child of its parent
s = x.parent.right # Sibling of x
if s.color == 1 : # if sibling is red
s.color = 0 # Set its color to black
x.parent.color = 1 # Make its parent red
self.LR ( x.parent ) # Call for left rotate on parent of x
s = x.parent.right
# If both the child are black
if s.left.color == 0 and s.right.color == 0 :
s.color = 1 # Set color of s as red
x = x.parent
else :
if s.right.color == 0 : # If right child of s is black
s.left.color = 0 # set left child of s as black
s.color = 1 # set color of s as red
self.RR ( s ) # call right rotation on x
s = x.parent.right

s.color = x.parent.color
x.parent.color = 0 # Set parent of x as black
s.right.color = 0
self.LR ( x.parent ) # call left rotation on parent of x
x = self.root
else : # If x is right child of its parent
s = x.parent.left # Sibling of x
if s.color == 1 : # if sibling is red
s.color = 0 # Set its color to black
x.parent.color = 1 # Make its parent red
self.RR ( x.parent ) # Call for right rotate on parent of x
s = x.parent.left

if s.right.color == 0 and s.right.color == 0 :
s.color = 1
x = x.parent
else :
if s.left.color == 0 : # If left child of s is black
s.right.color = 0 # set right child of s as black
s.color = 1
self.LR ( s ) # call left rotation on x
s = x.parent.left

s.color = x.parent.color
x.parent.color = 0
s.left.color = 0
self.RR ( x.parent )
x = self.root
x.color = 0


# Function to transplant nodes
def __rb_transplant ( self , u , v ) :
if u.parent == None :
self.root = v
elif u == u.parent.left :
u.parent.left = v
else :
u.parent.right = v
v.parent = u.parent


# Function to handle deletion
def delete_node_helper ( self , node , key ) :
z = self.NULL
while node != self.NULL : # Search for the node having that value/ key and store it in 'z'
if node.val == key :
z = node

if node.val <= key :
node = node.right
else :
node = node.left

if z == self.NULL : # If Kwy is not present then deletion not possible so return
print ( "Value not present in Tree !!" )
return

y = z
y_original_color = y.color # Store the color of z- node
if z.left == self.NULL : # If left child of z is NULL
x = z.right # Assign right child of z to x
self.__rb_transplant ( z , z.right ) # Transplant Node to be deleted with x
elif (z.right == self.NULL) : # If right child of z is NULL
x = z.left # Assign left child of z to x
self.__rb_transplant ( z , z.left ) # Transplant Node to be deleted with x
else : # If z has both the child nodes
y = self.minimum ( z.right ) # Find minimum of the right sub tree
y_original_color = y.color # Store color of y
x = y.right
if y.parent == z : # If y is child of z
x.parent = y # Set parent of x as y
else :
self.__rb_transplant ( y , y.right )
y.right = z.right
y.right.parent = y

self.__rb_transplant ( z , y )
y.left = z.left
y.left.parent = y
y.color = z.color
if y_original_color == 0 : # If color is black then fixing is needed
self.fixDelete ( x )


# Deletion of node
def delete_node ( self , val ) :
self.delete_node_helper ( self.root , val ) # Call for deletion


# Function to print
def __printCall ( self , node , indent , last ) :
if node != self.NULL :
print(indent, end=' ')
if last :
print ("R----",end= ' ')
indent += " "
else :
print("L----",end=' ')
indent += "| "

s_color = "RED" if node.color == 1 else "BLACK"
print ( str ( node.val ) + "(" + s_color + ")" )
self.__printCall ( node.left , indent , False )
self.__printCall ( node.right , indent , True )

# Function to call print
def print_tree ( self ) :
self.__printCall ( self.root , "" , True )


if __name__ == "__main__":
bst = RBTree()

bst.insertNode(10)
bst.insertNode(20)
bst.insertNode(30)
bst.insertNode(5)
bst.insertNode(4)
bst.insertNode(2)

bst.print_tree()

print("\nAfter deleting an element")
bst.delete_node(2)
bst.print_tree()
51 changes: 51 additions & 0 deletions Trees/pre-order traversal.py
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from collections import deque

class TreeNode:
def __init__(self, val=0, left=None, right=None):
self.val = val
self.left = left
self.right = right

def build_tree_from_list(lst):
if not lst or lst[0] is None:
return None

root = TreeNode(lst[0])
queue = deque([root])
i = 1

while i < len(lst):
node = queue.popleft()

# Process the left child
if i < len(lst) and lst[i] is not None:
node.left = TreeNode(lst[i])
queue.append(node.left)
i += 1

# Process the right child
if i < len(lst) and lst[i] is not None:
node.right = TreeNode(lst[i])
queue.append(node.right)
i += 1

return root

# Pre-order traversal function
def pre_order_traversal(root):
cur = root
stack = []
res = []
while cur or stack:
if cur:
res.append(cur.val)
stack.append(cur.right)
cur = cur.left
else:
cur = stack.pop()
return res

# Build the tree and perform pre-order traversal
lst = [1, 2, 3, 4, 5, None, 8, None, None, 6, 7, 9]
root = build_tree_from_list(lst)
print(pre_order_traversal(root))
6 changes: 6 additions & 0 deletions package-lock.json
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