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Merge branch 'master' into binary_search_tree

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Yudong Jin
2023-01-10 13:30:38 +08:00
committed by GitHub
parent 96d54bff3a a86bdeb7cd
commit daa28be3e4
215 changed files with 5618 additions and 1642 deletions
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23
codes/python/chapter_tree/binary_search_tree.py
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@@ -5,20 +5,18 @@ 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 *
""" 二叉搜索树 """
class BinarySearchTree:
def __init__(self, nums: typing.List[int]) -> None:
def __init__(self, nums: List[int]) -> None:
nums.sort()
self.__root = self.build_tree(nums, 0, len(nums) - 1)
""" 构建二叉搜索树 """
def build_tree(self, nums: typing.List[int], start_index: int, end_index: int) -> typing.Optional[TreeNode]:
def build_tree(self, nums: List[int], start_index: int, end_index: int) -> Optional[TreeNode]:
if start_index > end_index:
return None
@@ -31,11 +29,11 @@ class BinarySearchTree:
return root
@property
def root(self) -> typing.Optional[TreeNode]:
def root(self) -> Optional[TreeNode]:
return self.__root
""" 查找结点 """
def search(self, num: int) -> typing.Optional[TreeNode]:
def search(self, num: int) -> Optional[TreeNode]:
cur = self.root
# 循环查找，越过叶结点后跳出
while cur is not None:
@@ -51,7 +49,7 @@ class BinarySearchTree:
return cur
""" 插入结点 """
def insert(self, num: int) -> typing.Optional[TreeNode]:
def insert(self, num: int) -> Optional[TreeNode]:
root = self.root
# 若树为空，直接提前返回
if root is None:
@@ -81,7 +79,7 @@ class BinarySearchTree:
return node
""" 删除结点 """
def remove(self, num: int) -> typing.Optional[TreeNode]:
def remove(self, num: int) -> Optional[TreeNode]:
root = self.root
# 若树为空，直接提前返回
if root is None:
@@ -117,7 +115,7 @@ class BinarySearchTree:
# 子结点数量 = 2
else:
# 获取中序遍历中 cur 的下一个结点
nex = self.min(cur.right)
nex = self.get_inorder_next(cur.right)
tmp = nex.val
# 递归删除结点 nex
self.remove(nex.val)
@@ -125,11 +123,10 @@ class BinarySearchTree:
cur.val = tmp
return cur
""" 获取最小结点 """
def min(self, root: typing.Optional[TreeNode]) -> typing.Optional[TreeNode]:
""" 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, root: Optional[TreeNode]) -> Optional[TreeNode]:
if root is None:
return root
# 循环访问左子结点，直到叶结点时为最小结点，跳出
while root.left is not None:
root = root.left
@@ -139,7 +136,7 @@ class BinarySearchTree:
""" Driver Code """
if __name__ == "__main__":
# 初始化二叉搜索树
nums = list(range(1, 16))
nums = list(range(1, 16)) # [1, 2, ..., 15]
bst = BinarySearchTree(nums=nums)
print("\n初始化的二叉树为\n")
print_tree(bst.root)