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Update the Optional alias of Python codes.

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This commit is contained in:
Yudong Jin
2023-01-09 02:49:34 +08:00
parent 4d01436138
commit 97ee638d31
8 changed files with 37 additions and 45 deletions
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22
codes/python/chapter_tree/avl_tree.py
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@ -5,30 +5,28 @@ Author: a16su (lpluls001@gmail.com)
"""
import sys, os.path as osp
import typing
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from include import *
class AVLTree:
def __init__(self, root: typing.Optional[TreeNode] = None):
def __init__(self, root: Optional[TreeNode] = None):
self.root = root
""" 获取结点高度 """
def height(self, node: typing.Optional[TreeNode]) -> int:
def height(self, node: Optional[TreeNode]) -> int:
# 空结点高度为 -1 ，叶结点高度为 0
if node is not None:
return node.height
return -1
""" 更新结点高度 """
def __update_height(self, node: TreeNode):
def __update_height(self, node: Optional[TreeNode]):
# 结点高度等于最高子树高度 + 1
node.height = max([self.height(node.left), self.height(node.right)]) + 1
""" 获取平衡因子 """
def balance_factor(self, node: TreeNode) -> int:
def balance_factor(self, node: Optional[TreeNode]) -> int:
# 空结点平衡因子为 0
if node is None:
return 0
@ -36,7 +34,7 @@ class AVLTree:
return self.height(node.left) - self.height(node.right)
""" 右旋操作 """
def __right_rotate(self, node: TreeNode) -> TreeNode:
def __right_rotate(self, node: Optional[TreeNode]) -> TreeNode:
child = node.left
grand_child = child.right
# 以 child 为原点，将 node 向右旋转
@ -49,7 +47,7 @@ class AVLTree:
return child
""" 左旋操作 """
def __left_rotate(self, node: TreeNode) -> TreeNode:
def __left_rotate(self, node: Optional[TreeNode]) -> TreeNode:
child = node.right
grand_child = child.left
# 以 child 为原点，将 node 向左旋转
@ -62,7 +60,7 @@ class AVLTree:
return child
""" 执行旋转操作，使该子树重新恢复平衡 """
def __rotate(self, node: TreeNode) -> TreeNode:
def __rotate(self, node: Optional[TreeNode]) -> TreeNode:
# 获取结点 node 的平衡因子
balance_factor = self.balance_factor(node)
# 左偏树
@ -92,7 +90,7 @@ class AVLTree:
return self.root
""" 递归插入结点（辅助函数）"""
def __insert_helper(self, node: typing.Optional[TreeNode], val: int) -> TreeNode:
def __insert_helper(self, node: Optional[TreeNode], val: int) -> TreeNode:
if node is None:
return TreeNode(val)
# 1. 查找插入位置，并插入结点
@ -114,7 +112,7 @@ class AVLTree:
return root
""" 递归删除结点（辅助函数） """
def __remove_helper(self, node: typing.Optional[TreeNode], val: int) -> typing.Optional[TreeNode]:
def __remove_helper(self, node: Optional[TreeNode], val: int) -> Optional[TreeNode]:
if node is None:
return None
# 1. 查找结点，并删除之
@ -141,7 +139,7 @@ class AVLTree:
return self.__rotate(node)
""" 获取中序遍历中的下一个结点（仅适用于 root 有左子结点的情况） """
def __get_inorder_next(self, node: typing.Optional[TreeNode]) -> typing.Optional[TreeNode]:
def __get_inorder_next(self, node: Optional[TreeNode]) -> Optional[TreeNode]:
if node is None:
return None
# 循环访问左子结点，直到叶结点时为最小结点，跳出