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* fixup! Format Python code with psf/black push
This commit is contained in:
Christian Clauss
2019-12-26 12:50:12 +01:00
committed by John Law
parent 1b3985837f
commit 34c808b375
7 changed files with 128 additions and 117 deletions
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81
data_structures/binary_tree/binary_search_tree.py
View File

@ -1,6 +1,8 @@
'''
"""
A binary search Tree
'''
"""
class Node:
def __init__(self, value, parent):
self.value = value
@ -13,16 +15,11 @@ class Node:
if self.left is None and self.right is None:
return str(self.value)
return pformat(
{
"%s"
% (self.value): (self.left, self.right)
},
indent=1,
)
return pformat({"%s" % (self.value): (self.left, self.right)}, indent=1,)
class BinarySearchTree:
def __init__(self, root = None):
def __init__(self, root=None):
self.root = root
def __str__(self):
@ -32,10 +29,10 @@ class BinarySearchTree:
return str(self.root)
def __reassign_nodes(self, node, newChildren):
if(newChildren is not None): # reset its kids
if newChildren is not None: # reset its kids
newChildren.parent = node.parent
if(node.parent is not None): # reset its parent
if(self.is_right(node)): # If it is the right children
if node.parent is not None: # reset its parent
if self.is_right(node): # If it is the right children
node.parent.right = newChildren
else:
node.parent.left = newChildren
@ -55,10 +52,10 @@ class BinarySearchTree:
new_node = Node(value, None) # create a new Node
if self.empty(): # if Tree is empty
self.root = new_node # set its root
else: # Tree is not empty
parent_node = self.root # from root
else: # Tree is not empty
parent_node = self.root # from root
while True: # While we don't get to a leaf
if value < parent_node.value: # We go left
if value < parent_node.value: # We go left
if parent_node.left == None:
parent_node.left = new_node # We insert the new node in a leaf
break
@ -87,60 +84,65 @@ class BinarySearchTree:
node = node.left if value < node.value else node.right
return node
def get_max(self, node = None):
def get_max(self, node=None):
"""
We go deep on the right branch
"""
if node is None:
node = self.root
if not self.empty():
while(node.right is not None):
while node.right is not None:
node = node.right
return node
def get_min(self, node = None):
def get_min(self, node=None):
"""
We go deep on the left branch
"""
if(node is None):
if node is None:
node = self.root
if(not self.empty()):
if not self.empty():
node = self.root
while(node.left is not None):
while node.left is not None:
node = node.left
return node
def remove(self, value):
node = self.search(value) # Look for the node with that label
if(node is not None):
if(node.left is None and node.right is None): # If it has no children
node = self.search(value) # Look for the node with that label
if node is not None:
if node.left is None and node.right is None: # If it has no children
self.__reassign_nodes(node, None)
node = None
elif(node.left is None): # Has only right children
elif node.left is None: # Has only right children
self.__reassign_nodes(node, node.right)
elif(node.right is None): # Has only left children
elif node.right is None: # Has only left children
self.__reassign_nodes(node, node.left)
else:
tmpNode = self.get_max(node.left) # Gets the max value of the left branch
tmpNode = self.get_max(
node.left
) # Gets the max value of the left branch
self.remove(tmpNode.value)
node.value = tmpNode.value # Assigns the value to the node to delete and keesp tree structure
node.value = (
tmpNode.value
) # Assigns the value to the node to delete and keesp tree structure
def preorder_traverse(self, node):
if node is not None:
yield node # Preorder Traversal
yield from self.preorder_traverse(node.left)
yield from self.preorder_traverse(node.right)
def traversal_tree(self, traversalFunction = None):
def traversal_tree(self, traversalFunction=None):
"""
This function traversal the tree.
You can pass a function to traversal the tree as needed by client code
"""
if(traversalFunction is None):
if traversalFunction is None:
return self.preorder_traverse(self.root)
else:
return traversalFunction(self.root)
def postorder(curr_node):
"""
postOrder (left, right, self)
@ -150,8 +152,9 @@ def postorder(curr_node):
nodeList = postorder(curr_node.left) + postorder(curr_node.right) + [curr_node]
return nodeList
def binary_search_tree():
r'''
r"""
Example
8
/ \
@ -170,7 +173,7 @@ def binary_search_tree():
Traceback (most recent call last):
...
IndexError: Warning: Tree is empty! please use another.
'''
"""
testlist = (8, 3, 6, 1, 10, 14, 13, 4, 7)
t = BinarySearchTree()
for i in testlist:
@ -178,18 +181,18 @@ def binary_search_tree():
# Prints all the elements of the list in order traversal
print(t)
if(t.search(6) is not None):
if t.search(6) is not None:
print("The value 6 exists")
else:
print("The value 6 doesn't exist")
if(t.search(-1) is not None):
if t.search(-1) is not None:
print("The value -1 exists")
else:
print("The value -1 doesn't exist")
if(not t.empty()):
if not t.empty():
print("Max Value: ", t.get_max().value)
print("Min Value: ", t.get_min().value)
@ -197,9 +200,11 @@ def binary_search_tree():
t.remove(i)
print(t)
二叉搜索树 = binary_search_tree
if __name__ == "__main__":
import doctest
doctest.testmod()
binary_search_tree()