algorithm/hello-algo
1
0
Fork 0
mirror of https://github.com/krahets/hello-algo.git synced 2025-11-02 12:58:42 +08:00
Code Issues Packages Projects Releases Wiki Activity

Format python codes with black. (#453)

Browse Source
This commit is contained in:
Yudong Jin
2023-04-09 05:05:35 +08:00
committed by GitHub
parent 1c8b7ef559
commit 5ddcb60825
45 changed files with 656 additions and 456 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
codes/python/chapter_tree/avl_tree.py
View File

@ -5,13 +5,16 @@ Author: a16su (lpluls001@gmail.com)
"""
import sys, os.path as osp
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from modules import *
class AVLTree:
""" AVL 树 """
"""AVL 树"""
def __init__(self, root: TreeNode | None = None):
""" 构造方法 """
"""构造方法"""
self.__root = root
@property
@ -19,19 +22,19 @@ class AVLTree:
return self.__root
def height(self, node: TreeNode | None) -> int:
""" 获取节点高度 """
"""获取节点高度"""
# 空节点高度为 -1 ，叶节点高度为 0
if node is not None:
return node.height
return -1
def __update_height(self, node: TreeNode | None):
""" 更新节点高度 """
"""更新节点高度"""
# 节点高度等于最高子树高度 + 1
node.height = max([self.height(node.left), self.height(node.right)]) + 1
def balance_factor(self, node: TreeNode | None) -> int:
""" 获取平衡因子 """
"""获取平衡因子"""
# 空节点平衡因子为 0
if node is None:
return 0
@ -39,7 +42,7 @@ class AVLTree:
return self.height(node.left) - self.height(node.right)
def __right_rotate(self, node: TreeNode | None) -> TreeNode | None:
""" 右旋操作 """
"""右旋操作"""
child = node.left
grand_child = child.right
# 以 child 为原点，将 node 向右旋转
@ -52,7 +55,7 @@ class AVLTree:
return child
def __left_rotate(self, node: TreeNode | None) -> TreeNode | None:
""" 左旋操作 """
"""左旋操作"""
child = node.right
grand_child = child.left
# 以 child 为原点，将 node 向左旋转
@ -65,7 +68,7 @@ class AVLTree:
return child
def __rotate(self, node: TreeNode | None) -> TreeNode | None:
""" 执行旋转操作，使该子树重新恢复平衡 """
"""执行旋转操作，使该子树重新恢复平衡"""
# 获取节点 node 的平衡因子
balance_factor = self.balance_factor(node)
# 左偏树
@ -90,12 +93,12 @@ class AVLTree:
return node
def insert(self, val) -> TreeNode:
""" 插入节点 """
"""插入节点"""
self.__root = self.__insert_helper(self.__root, val)
return self.__root
def __insert_helper(self, node: TreeNode | None, val: int) -> TreeNode:
""" 递归插入节点（辅助方法）"""
"""递归插入节点（辅助方法）"""
if node is None:
return TreeNode(val)
# 1. 查找插入位置，并插入节点
@ -112,12 +115,12 @@ class AVLTree:
return self.__rotate(node)
def remove(self, val: int) -> TreeNode | None:
""" 删除节点 """
"""删除节点"""
self.__root = self.__remove_helper(self.__root, val)
return self.__root
return self.__root
def __remove_helper(self, node: TreeNode | None, val: int) -> TreeNode | None:
""" 递归删除节点（辅助方法） """
"""递归删除节点（辅助方法）"""
if node is None:
return None
# 1. 查找节点，并删除之
@ -144,7 +147,7 @@ class AVLTree:
return self.__rotate(node)
def __get_inorder_next(self, node: TreeNode | None) -> TreeNode | None:
""" 获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况） """
"""获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况）"""
if node is None:
return None
# 循环访问左子节点，直到叶节点时为最小节点，跳出
@ -153,7 +156,7 @@ class AVLTree:
return node
def search(self, val: int) -> TreeNode | None:
""" 查找节点 """
"""查找节点"""
cur = self.__root
# 循环查找，越过叶节点后跳出
while cur is not None:
@ -172,6 +175,7 @@ class AVLTree:
""" Driver Code """
if __name__ == "__main__":
def test_insert(tree: AVLTree, val: int):
tree.insert(val)
print("\n插入节点 {} 后，AVL 树为".format(val))

32
codes/python/chapter_tree/binary_search_tree.py
View File

@ -5,19 +5,23 @@ Author: a16su (lpluls001@gmail.com)
"""
import sys, os.path as osp
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from modules import *
class BinarySearchTree:
""" 二叉搜索树 """
"""二叉搜索树"""
def __init__(self, nums: list[int]) -> None:
""" 构造方法 """
"""构造方法"""
nums.sort()
self.__root = self.build_tree(nums, 0, len(nums) - 1)
def build_tree(self, nums: list[int], start_index: int, end_index: int) -> TreeNode | None:
""" 构建二叉搜索树 """
def build_tree(
self, nums: list[int], start_index: int, end_index: int
) -> TreeNode | None:
"""构建二叉搜索树"""
if start_index > end_index:
return None
@ -25,8 +29,12 @@ class BinarySearchTree:
mid: int = (start_index + end_index) // 2
root = TreeNode(nums[mid])
# 递归建立左子树和右子树
root.left = self.build_tree(nums=nums, start_index=start_index, end_index=mid - 1)
root.right = self.build_tree(nums=nums, start_index=mid + 1, end_index=end_index)
root.left = self.build_tree(
nums=nums, start_index=start_index, end_index=mid - 1
)
root.right = self.build_tree(
nums=nums, start_index=mid + 1, end_index=end_index
)
return root
@property
@ -34,7 +42,7 @@ class BinarySearchTree:
return self.__root
def search(self, num: int) -> TreeNode | None:
""" 查找节点 """
"""查找节点"""
cur: TreeNode | None = self.__root
# 循环查找，越过叶节点后跳出
while cur is not None:
@ -50,11 +58,11 @@ class BinarySearchTree:
return cur
def insert(self, num: int) -> TreeNode | None:
""" 插入节点 """
"""插入节点"""
# 若树为空，直接提前返回
if self.__root is None:
return None
# 循环查找，越过叶节点后跳出
cur, pre = self.__root, None
while cur is not None:
@ -78,7 +86,7 @@ class BinarySearchTree:
return node
def remove(self, num: int) -> TreeNode | None:
""" 删除节点 """
"""删除节点"""
# 若树为空，直接提前返回
if self.__root is None:
return None
@ -119,7 +127,7 @@ class BinarySearchTree:
return cur
def get_inorder_next(self, root: TreeNode | None) -> TreeNode | None:
""" 获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况） """
"""获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况）"""
if root is None:
return root
# 循环访问左子节点，直到叶节点时为最小节点，跳出
@ -131,7 +139,7 @@ class BinarySearchTree:
""" Driver Code """
if __name__ == "__main__":
# 初始化二叉搜索树
nums = list(range(1, 16)) # [1, 2, ..., 15]
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)

4
codes/python/chapter_tree/binary_tree.py
View File

@ -12,7 +12,7 @@ from modules import *
""" Driver Code """
if __name__ == "__main__":
""" 初始化二叉树 """
# 初始化二叉树
# 初始化节点
n1 = TreeNode(val=1)
n2 = TreeNode(val=2)
@ -27,7 +27,7 @@ if __name__ == "__main__":
print("\n初始化二叉树\n")
print_tree(n1)
""" 插入与删除节点 """
# 插入与删除节点
P = TreeNode(0)
# 在 n1 -> n2 中间插入节点 P
n1.left = P

12
codes/python/chapter_tree/binary_tree_bfs.py
View File

@ -5,24 +5,26 @@ Author: a16su (lpluls001@gmail.com)
"""
import sys, os.path as osp
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from modules import *
from collections import deque
def level_order(root: TreeNode | None) -> list[int]:
""" 层序遍历 """
"""层序遍历"""
# 初始化队列，加入根节点
queue: deque[TreeNode] = deque()
queue.append(root)
# 初始化一个列表，用于保存遍历序列
res: list[int] = []
while queue:
node: TreeNode = queue.popleft() # 队列出队
res.append(node.val) # 保存节点值
node: TreeNode = queue.popleft() # 队列出队
res.append(node.val) # 保存节点值
if node.left is not None:
queue.append(node.left) # 左子节点入队
queue.append(node.left) # 左子节点入队
if node.right is not None:
queue.append(node.right) # 右子节点入队
queue.append(node.right) # 右子节点入队
return res

10
codes/python/chapter_tree/binary_tree_dfs.py
View File

@ -5,11 +5,13 @@ Author: a16su (lpluls001@gmail.com)
"""
import sys, os.path as osp
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from modules import *
def pre_order(root: TreeNode | None) -> None:
""" 前序遍历 """
"""前序遍历"""
if root is None:
return
# 访问优先级：根节点 -> 左子树 -> 右子树
@ -17,8 +19,9 @@ def pre_order(root: TreeNode | None) -> None:
pre_order(root=root.left)
pre_order(root=root.right)
def in_order(root: TreeNode | None) -> None:
""" 中序遍历 """
"""中序遍历"""
if root is None:
return
# 访问优先级：左子树 -> 根节点 -> 右子树
@ -26,8 +29,9 @@ def in_order(root: TreeNode | None) -> None:
res.append(root.val)
in_order(root=root.right)
def post_order(root: TreeNode | None) -> None:
""" 后序遍历 """
"""后序遍历"""
if root is None:
return
# 访问优先级：左子树 -> 右子树 -> 根节点