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types: Update binary search tree typehints (#7197)

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* types: Update binary search tree typehints

* refactor: Don't return `self` in `:meth:insert`

* test: Fix failing doctests

* Apply suggestions from code review

Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
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Caeden 2022-10-15 23:51:23 +01:00 committed by GitHub
parent 553624fcd4
commit c94e215c8d
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1 changed files with 44 additions and 33 deletions
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77
data_structures/binary_tree/binary_search_tree.py
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@ -2,15 +2,18 @@
A binary search Tree
"""
from collections.abc import Iterable
from typing import Any
class Node:
def __init__(self, value, parent):
def __init__(self, value: int | None = None):
self.value = value
self.parent = parent # Added in order to delete a node easier
self.left = None
self.right = None
self.parent: Node | None = None # Added in order to delete a node easier
self.left: Node | None = None
self.right: Node | None = None
def __repr__(self):
def __repr__(self) -> str:
from pprint import pformat
if self.left is None and self.right is None:
@ -19,16 +22,16 @@ class Node:
class BinarySearchTree:
def __init__(self, root=None):
def __init__(self, root: Node | None = None):
self.root = root
def __str__(self):
def __str__(self) -> str:
"""
Return a string of all the Nodes using in order traversal
"""
return str(self.root)
def __reassign_nodes(self, node, new_children):
def __reassign_nodes(self, node: Node, new_children: Node | None) -> None:
if new_children is not None: # reset its kids
new_children.parent = node.parent
if node.parent is not None: # reset its parent
@ -37,23 +40,27 @@ class BinarySearchTree:
else:
node.parent.left = new_children
else:
self.root = new_children
self.root = None
def is_right(self, node):
return node == node.parent.right
def is_right(self, node: Node) -> bool:
if node.parent and node.parent.right:
return node == node.parent.right
return False
def empty(self):
def empty(self) -> bool:
return self.root is None
def __insert(self, value):
def __insert(self, value) -> None:
"""
Insert a new node in Binary Search Tree with value label
"""
new_node = Node(value, None) # create a new Node
new_node = Node(value) # 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
if parent_node is None:
return None
while True: # While we don't get to a leaf
if value < parent_node.value: # We go left
if parent_node.left is None:
@ -69,12 +76,11 @@ class BinarySearchTree:
parent_node = parent_node.right
new_node.parent = parent_node
def insert(self, *values):
def insert(self, *values) -> None:
for value in values:
self.__insert(value)
return self
def search(self, value):
def search(self, value) -> Node | None:
if self.empty():
raise IndexError("Warning: Tree is empty! please use another.")
else:
@ -84,30 +90,35 @@ 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: Node | None = None) -> Node | None:
"""
We go deep on the right branch
"""
if node is None:
if self.root is None:
return None
node = self.root
if not self.empty():
while node.right is not None:
node = node.right
return node
def get_min(self, node=None):
def get_min(self, node: Node | None = None) -> Node | None:
"""
We go deep on the left branch
"""
if node is None:
node = self.root
if self.root is None:
return None
if not self.empty():
node = self.root
while node.left is not None:
node = node.left
return node
def remove(self, value):
def remove(self, value: int) -> None:
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
@ -120,18 +131,18 @@ class BinarySearchTree:
tmp_node = self.get_max(
node.left
) # Gets the max value of the left branch
self.remove(tmp_node.value)
self.remove(tmp_node.value) # type: ignore
node.value = (
tmp_node.value
tmp_node.value # type: ignore
) # Assigns the value to the node to delete and keep tree structure
def preorder_traverse(self, node):
def preorder_traverse(self, node: Node | None) -> Iterable:
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, traversal_function=None):
def traversal_tree(self, traversal_function=None) -> Any:
"""
This function traversal the tree.
You can pass a function to traversal the tree as needed by client code
@ -141,7 +152,7 @@ class BinarySearchTree:
else:
return traversal_function(self.root)
def inorder(self, arr: list, node: Node):
def inorder(self, arr: list, node: Node | None) -> None:
"""Perform an inorder traversal and append values of the nodes to
a list named arr"""
if node:
@ -151,12 +162,12 @@ class BinarySearchTree:
def find_kth_smallest(self, k: int, node: Node) -> int:
"""Return the kth smallest element in a binary search tree"""
arr: list = []
arr: list[int] = []
self.inorder(arr, node) # append all values to list using inorder traversal
return arr[k - 1]
def postorder(curr_node):
def postorder(curr_node: Node | None) -> list[Node]:
"""
postOrder (left, right, self)
"""
@ -166,7 +177,7 @@ def postorder(curr_node):
return node_list
def binary_search_tree():
def binary_search_tree() -> None:
r"""
Example
8
@ -177,7 +188,8 @@ def binary_search_tree():
/ \ /
4 7 13
>>> t = BinarySearchTree().insert(8, 3, 6, 1, 10, 14, 13, 4, 7)
>>> t = BinarySearchTree()
>>> t.insert(8, 3, 6, 1, 10, 14, 13, 4, 7)
>>> print(" ".join(repr(i.value) for i in t.traversal_tree()))
8 3 1 6 4 7 10 14 13
>>> print(" ".join(repr(i.value) for i in t.traversal_tree(postorder)))
@ -206,8 +218,8 @@ def binary_search_tree():
print("The value -1 doesn't exist")
if not t.empty():
print("Max Value: ", t.get_max().value)
print("Min Value: ", t.get_min().value)
print("Max Value: ", t.get_max().value) # type: ignore
print("Min Value: ", t.get_min().value) # type: ignore
for i in testlist:
t.remove(i)
@ -217,5 +229,4 @@ def binary_search_tree():
if __name__ == "__main__":
import doctest
doctest.testmod()
# binary_search_tree()
doctest.testmod(verbose=True)