mirror of
https://github.com/krahets/hello-algo.git
synced 2025-01-23 22:40:25 +08:00
fix format error
This commit is contained in:
a16su
parent
9eac1275f6
commit
8b401c2acb
@ -1,3 +1,9 @@
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"""
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File: avl_tree.py
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Created Time: 2022-12-20
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Author: a16su (lpluls001@gmail.com)
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"""
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import sys, os.path as osp
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import typing
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@ -5,75 +11,36 @@ sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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from include import *
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class AVLTreeNode:
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def __init__(
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self,
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val=None,
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height: int = 0,
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left: typing.Optional["AVLTreeNode"] = None,
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right: typing.Optional["AVLTreeNode"] = None,
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):
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self.val = val
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self.height = height
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self.left = left
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self.right = right
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def __str__(self):
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val = self.val
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left_val = self.left.val if self.left else None
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right_val = self.right.val if self.right else None
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return "<AVLTreeNode: {}, leftAVLTreeNode: {}, rightAVLTreeNode: {}>".format(
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val, left_val, right_val
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)
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class AVLTree:
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def __init__(self, root: typing.Optional[AVLTreeNode] = None):
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def __init__(self, root: typing.Optional[TreeNode] = None):
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self.root = root
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@staticmethod
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def height(node: typing.Optional[AVLTreeNode]) -> int:
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"""
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获取结点高度
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Args:
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node:起始结点
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""" 获取结点高度 """
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Returns: 高度 or -1
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"""
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def height(self, node: typing.Optional[TreeNode]) -> int:
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# 空结点高度为 -1 ，叶结点高度为 0
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if node is not None:
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return node.height
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return -1
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def __update_height(self, node: AVLTreeNode):
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"""
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更新结点高度
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Args:
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node: 要更新高度的结点
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""" 更新结点高度 """
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Returns: None
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"""
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def __update_height(self, node: TreeNode):
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# 结点高度等于最高子树高度 + 1
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node.height = max([self.height(node.left), self.height(node.right)]) + 1
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def balance_factor(self, node: AVLTreeNode) -> int:
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"""
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获取结点平衡因子
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Args:
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node: 要获取平衡因子的结点
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""" 获取平衡因子 """
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Returns: 平衡因子
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"""
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def balance_factor(self, node: TreeNode) -> int:
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# 空结点平衡因子为 0
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if node is None:
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return 0
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# 结点平衡因子 = 左子树高度 - 右子树高度
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return self.height(node.left) - self.height(node.right)
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def __right_rotate(self, node: AVLTreeNode) -> AVLTreeNode:
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""" 右旋操作 """
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def __right_rotate(self, node: TreeNode) -> TreeNode:
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child = node.left
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grand_child = child.right
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# 以 child 为原点，将 node 向右旋转
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@ -85,7 +52,9 @@ class AVLTree:
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# 返回旋转后子树的根节点
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return child
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def __left_rotate(self, node: AVLTreeNode) -> AVLTreeNode:
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""" 左旋操作 """
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def __left_rotate(self, node: TreeNode) -> TreeNode:
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child = node.right
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grand_child = child.left
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# 以 child 为原点，将 node 向左旋转
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@ -97,15 +66,9 @@ class AVLTree:
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# 返回旋转后子树的根节点
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return child
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def rotate(self, node: AVLTreeNode):
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"""
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执行旋转操作，使该子树重新恢复平衡
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Args:
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node: 要旋转的根结点
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""" 执行旋转操作，使该子树重新恢复平衡 """
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Returns: 旋转后的根结点
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"""
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def __rotate(self, node: TreeNode) -> TreeNode:
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# 获取结点 node 的平衡因子
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balance_factor = self.balance_factor(node)
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# 左偏树
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@ -129,76 +92,46 @@ class AVLTree:
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# 平衡树，无需旋转，直接返回
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return node
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def insert(self, val) -> AVLTreeNode:
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"""
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插入结点
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Args:
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val: 结点的值
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""" 插入结点 """
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Returns:
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node: 插入结点后的根结点
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"""
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self.root = self.insert_helper(self.root, val)
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def insert(self, val) -> TreeNode:
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self.root = self.__insert_helper(self.root, val)
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return self.root
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def insert_helper(
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self, node: typing.Optional[AVLTreeNode], val: int
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) -> AVLTreeNode:
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"""
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递归插入结点（辅助函数）
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Args:
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node: 要插入的根结点
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val: 要插入的结点的值
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""" 递归插入结点（辅助函数）"""
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Returns: 插入结点后的根结点
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"""
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def __insert_helper(self, node: typing.Optional[TreeNode], val: int) -> TreeNode:
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if node is None:
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return AVLTreeNode(val)
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return TreeNode(val)
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# 1. 查找插入位置，并插入结点
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if val < node.val:
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node.left = self.insert_helper(node.left, val)
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node.left = self.__insert_helper(node.left, val)
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elif val > node.val:
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node.right = self.insert_helper(node.right, val)
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node.right = self.__insert_helper(node.right, val)
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else:
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# 重复结点不插入，直接返回
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return node
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# 更新结点高度
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self.__update_height(node)
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# 2. 执行旋转操作，使该子树重新恢复平衡
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return self.rotate(node)
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return self.__rotate(node)
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""" 删除结点 """
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def remove(self, val: int):
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"""
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删除结点
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Args:
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val: 要删除的结点的值
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Returns:
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"""
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root = self.remove_helper(self.root, val)
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root = self.__remove_helper(self.root, val)
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return root
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def remove_helper(
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self, node: typing.Optional[AVLTreeNode], val: int
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) -> typing.Optional[AVLTreeNode]:
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"""
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递归删除结点（辅助函数）
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Args:
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node: 删除的起始结点
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val: 要删除的结点的值
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""" 递归删除结点（辅助函数） """
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Returns: 删除目标结点后的起始结点
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"""
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def __remove_helper(self, node: typing.Optional[TreeNode], val: int) -> typing.Optional[TreeNode]:
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if node is None:
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return None
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# 1. 查找结点，并删除之
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if val < node.val:
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node.left = self.remove_helper(node.left, val)
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node.left = self.__remove_helper(node.left, val)
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elif val > node.val:
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node.right = self.remove_helper(node.right, val)
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node.right = self.__remove_helper(node.right, val)
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else:
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if node.left is None or node.right is None:
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child = node.left or node.right
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@ -210,17 +143,16 @@ class AVLTree:
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node = child
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else: # 子结点数量 = 2 ，则将中序遍历的下个结点删除，并用该结点替换当前结点
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temp = self.min_node(node.right)
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node.right = self.remove_helper(node.right, temp.val)
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node.right = self.__remove_helper(node.right, temp.val)
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node.val = temp.val
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# 更新结点高度
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self.__update_height(node)
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# 2. 执行旋转操作，使该子树重新恢复平衡
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return self.rotate(node)
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return self.__rotate(node)
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def min_node(
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self, node: typing.Optional[AVLTreeNode]
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) -> typing.Optional[AVLTreeNode]:
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# 获取最小结点
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""" 获取最小结点 """
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def min_node(self, node: typing.Optional[TreeNode]) -> typing.Optional[TreeNode]:
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if node is None:
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return None
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# 循环访问左子结点，直到叶结点时为最小结点，跳出
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@ -228,15 +160,22 @@ class AVLTree:
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node = node.left
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return node
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""" 查找结点 """
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def search(self, val: int):
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cur = self.root
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# 循环查找，越过叶结点后跳出
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while cur is not None:
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# 目标结点在 root 的右子树中
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if cur.val < val:
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cur = cur.right
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# 目标结点在 root 的左子树中
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elif cur.val > val:
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cur = cur.left
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# 找到目标结点，跳出循环
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else:
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break
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# 返回目标结点
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return cur
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@ -1,43 +1,46 @@
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"""
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File: binary_search_tree.py
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Created Time: 2022-11-25
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Author: Krahets (krahets@163.com)
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Created Time: 2022-12-20
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Author: a16su (lpluls001@gmail.com)
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"""
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import sys, os.path as osp
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import typing
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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from include import *
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""" 二叉搜索树 """
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class BinarySearchTree:
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"""
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二叉搜索树
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"""
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def __init__(self, nums) -> None:
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def __init__(self, nums: typing.List[int]) -> None:
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nums.sort()
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self.__root = self.buildTree(nums, 0, len(nums) - 1)
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self.__root = self.build_tree(nums, 0, len(nums) - 1)
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def buildTree(self, nums, start_index, end_index):
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""" 构建二叉搜索树 """
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def build_tree(self, nums: typing.List[int], start_index: int, end_index: int) -> typing.Optional[TreeNode]:
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if start_index > end_index:
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return None
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# 将数组中间结点作为根结点
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mid = (start_index + end_index) // 2
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root = TreeNode(nums[mid])
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root.left = self.buildTree(
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nums=nums, start_index=start_index, end_index=mid - 1
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)
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root.right = self.buildTree(nums=nums, start_index=mid + 1, end_index=end_index)
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# 递归建立左子树和右子树
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root.left = self.build_tree(nums=nums, start_index=start_index, end_index=mid - 1)
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root.right = self.build_tree(nums=nums, start_index=mid + 1, end_index=end_index)
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return root
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def get_root(self):
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@property
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def root(self) -> typing.Optional[TreeNode]:
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return self.__root
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def search(self, num):
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"""
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查找结点
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"""
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cur = self.get_root()
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""" 查找结点 """
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def search(self, num: int) -> typing.Optional[TreeNode]:
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cur = self.root
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# 循环查找，越过叶结点后跳出
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while cur is not None:
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# 目标结点在 root 的右子树中
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@ -51,11 +54,10 @@ class BinarySearchTree:
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break
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return cur
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def insert(self, num):
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"""
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插入结点
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"""
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root = self.get_root()
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""" 插入结点 """
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def insert(self, num: int) -> typing.Optional[TreeNode]:
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root = self.root
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# 若树为空，直接提前返回
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if root is None:
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return None
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@ -83,11 +85,10 @@ class BinarySearchTree:
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pre.left = node
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return node
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def remove(self, num):
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"""
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删除结点
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"""
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root = self.get_root()
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""" 删除结点 """
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def remove(self, num: int) -> typing.Optional[TreeNode]:
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root = self.root
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# 若树为空，直接提前返回
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if root is None:
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return None
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@ -130,10 +131,9 @@ class BinarySearchTree:
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cur.val = tmp
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return cur
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def min(self, root):
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"""
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获取最小结点
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"""
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""" 获取最小结点 """
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def min(self, root: typing.Optional[TreeNode]) -> typing.Optional[TreeNode]:
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if root is None:
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return root
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@ -148,7 +148,7 @@ if __name__ == "__main__":
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nums = list(range(1, 16))
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bst = BinarySearchTree(nums=nums)
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print("\n初始化的二叉树为\n")
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print_tree(bst.get_root())
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print_tree(bst.root)
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# 查找结点
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node = bst.search(5)
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@ -157,17 +157,17 @@ if __name__ == "__main__":
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# 插入结点
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ndoe = bst.insert(16)
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print("\n插入结点 16 后，二叉树为\n")
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print_tree(bst.get_root())
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print_tree(bst.root)
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# 删除结点
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bst.remove(1)
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print("\n删除结点 1 后，二叉树为\n")
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print_tree(bst.get_root())
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print_tree(bst.root)
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bst.remove(2)
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print("\n删除结点 2 后，二叉树为\n")
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print_tree(bst.get_root())
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print_tree(bst.root)
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bst.remove(4)
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print("\n删除结点 4 后，二叉树为\n")
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print_tree(bst.get_root())
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print_tree(bst.root)
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@ -1,7 +1,7 @@
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"""
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File: binary_tree.py
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Created Time: 2022-11-25
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Author: Krahets (krahets@163.com)
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Created Time: 2022-12-20
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Author: a16su (lpluls001@gmail.com)
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"""
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import sys, os.path as osp
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@ -1,17 +1,22 @@
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"""
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File: binary_tree_bfs.py
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Created Time: 2022-11-25
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Author: Krahets (krahets@163.com)
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Created Time: 2022-12-20
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Author: a16su (lpluls001@gmail.com)
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"""
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import sys, os.path as osp
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import typing
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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from include import *
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def hierOrder(root):
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""" 层序遍历 """
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def hier_order(root: TreeNode):
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# 初始化队列，加入根结点
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queue = collections.deque()
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queue: typing.Deque[TreeNode] = collections.deque()
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queue.append(root)
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# 初始化一个列表，用于保存遍历序列
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result = []
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@ -33,13 +38,11 @@ def hierOrder(root):
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if __name__ == "__main__":
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# 初始化二叉树
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# 这里借助了一个从数组直接生成二叉树的函数
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root = list_to_tree(
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arr=[1, 2, 3, 4, 5, 6, 7, None, None, None, None, None, None, None, None]
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)
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root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7, None, None, None, None, None, None, None, None])
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print("\n初始化二叉树\n")
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print_tree(root)
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# 层序遍历
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result = hierOrder(root)
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result = hier_order(root)
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print("\n层序遍历的结点打印序列 = ", result)
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assert result == [1, 2, 3, 4, 5, 6, 7]
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assert result == [1, 2, 3, 4, 5, 6, 7]
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@ -1,10 +1,12 @@
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"""
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File: binary_tree_dfs.py
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Created Time: 2022-11-25
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Author: Krahets (krahets@163.com)
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Created Time: 2022-12-20
|
||||
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 *
|
||||
|
||||
@ -12,42 +14,42 @@ from include import *
|
||||
result = []
|
||||
|
||||
|
||||
def preOrder(root):
|
||||
"""
|
||||
前序遍历二叉树
|
||||
"""
|
||||
""" 前序遍历二叉树 """
|
||||
|
||||
|
||||
def pre_order(root: typing.Optional[TreeNode]):
|
||||
if root is None:
|
||||
return
|
||||
|
||||
# 访问优先级：根结点 -> 左子树 -> 右子树
|
||||
result.append(root.val)
|
||||
preOrder(root=root.left)
|
||||
preOrder(root=root.right)
|
||||
pre_order(root=root.left)
|
||||
pre_order(root=root.right)
|
||||
|
||||
|
||||
def inOrder(root):
|
||||
"""
|
||||
中序遍历二叉树
|
||||
"""
|
||||
""" 中序遍历二叉树 """
|
||||
|
||||
|
||||
def in_order(root: typing.Optional[TreeNode]):
|
||||
if root is None:
|
||||
return
|
||||
|
||||
# 访问优先级：左子树 -> 根结点 -> 右子树
|
||||
inOrder(root=root.left)
|
||||
in_order(root=root.left)
|
||||
result.append(root.val)
|
||||
inOrder(root=root.right)
|
||||
in_order(root=root.right)
|
||||
|
||||
|
||||
def postOrder(root):
|
||||
"""
|
||||
后序遍历二叉树
|
||||
"""
|
||||
""" 后序遍历二叉树 """
|
||||
|
||||
|
||||
def post_order(root: typing.Optional[TreeNode]):
|
||||
if root is None:
|
||||
return
|
||||
|
||||
# 访问优先级：左子树 -> 右子树 -> 根结点
|
||||
postOrder(root=root.left)
|
||||
postOrder(root=root.right)
|
||||
post_order(root=root.left)
|
||||
post_order(root=root.right)
|
||||
result.append(root.val)
|
||||
|
||||
|
||||
@ -55,26 +57,24 @@ def postOrder(root):
|
||||
if __name__ == "__main__":
|
||||
# 初始化二叉树
|
||||
# 这里借助了一个从数组直接生成二叉树的函数
|
||||
root = list_to_tree(
|
||||
arr=[1, 2, 3, 4, 5, 6, 7, None, None, None, None, None, None, None, None]
|
||||
)
|
||||
root = list_to_tree(arr=[1, 2, 3, 4, 5, 6, 7, None, None, None, None, None, None, None, None])
|
||||
print("\n初始化二叉树\n")
|
||||
print_tree(root)
|
||||
|
||||
# 前序遍历
|
||||
result = []
|
||||
preOrder(root)
|
||||
result.clear()
|
||||
pre_order(root)
|
||||
print("\n前序遍历的结点打印序列 = ", result)
|
||||
assert result == [1, 2, 4, 5, 3, 6, 7]
|
||||
|
||||
# 中序遍历
|
||||
result = []
|
||||
inOrder(root)
|
||||
result.clear()
|
||||
in_order(root)
|
||||
print("\n中序遍历的结点打印序列 = ", result)
|
||||
assert result == [4, 2, 5, 1, 6, 3, 7]
|
||||
|
||||
# 后序遍历
|
||||
result = []
|
||||
postOrder(root)
|
||||
result.clear()
|
||||
post_order(root)
|
||||
print("\n后序遍历的结点打印序列 = ", result)
|
||||
assert result == [4, 5, 2, 6, 7, 3, 1]
|
||||
assert result == [4, 5, 2, 6, 7, 3, 1]
|
||||
|
||||
@ -10,9 +10,19 @@ class TreeNode:
|
||||
"""Definition for a binary tree node
|
||||
"""
|
||||
def __init__(self, val=None, left=None, right=None):
|
||||
self.val = val
|
||||
self.left = left
|
||||
self.right = right
|
||||
self.val = val # 结点值
|
||||
self.height = 0 # 结点高度, avl 树会用到
|
||||
self.left = left # 左子结点引用
|
||||
self.right = right # 右子结点引用
|
||||
|
||||
def __str__(self): # 直接print时会好看一点
|
||||
val = self.val
|
||||
left_node_val = self.left.val if self.left else None
|
||||
right_node_val = self.right.val if self.right else None
|
||||
return "<TreeNode: {}, leftTreeNode: {}, rightTreeNode: {}>".format(val, left_node_val, right_node_val)
|
||||
|
||||
__repr__ = __str__
|
||||
|
||||
|
||||
def list_to_tree(arr):
|
||||
"""Generate a binary tree with a list
|
||||
|
||||
@ -48,24 +48,21 @@ G. M. Adelson-Velsky 和 E. M. Landis 在其 1962 年发表的论文 "An algorit
|
||||
=== "Python"
|
||||
|
||||
```python title="avl_tree.py"
|
||||
class AVLTreeNode:
|
||||
def __init__(
|
||||
self,
|
||||
val=None,
|
||||
height: int = 0,
|
||||
left: typing.Optional["AVLTreeNode"] = None,
|
||||
right: typing.Optional["AVLTreeNode"] = None
|
||||
):
|
||||
self.val = val
|
||||
self.height = height
|
||||
self.left = left
|
||||
self.right = right
|
||||
""" AVL 树结点类 """
|
||||
class TreeNode:
|
||||
def __init__(self, val=None, left=None, right=None):
|
||||
self.val = val # 结点值
|
||||
self.height = 0 # 结点高度, avl 树会用到
|
||||
self.left = left # 左子结点引用
|
||||
self.right = right # 右子结点引用
|
||||
|
||||
def __str__(self):
|
||||
def __str__(self): # 直接print时会好看一点
|
||||
val = self.val
|
||||
left_val = self.left.val if self.left else None
|
||||
right_val = self.right.val if self.right else None
|
||||
return "<AVLTreeNode: {}, leftAVLTreeNode: {}, rightAVLTreeNode: {}>".format(val, left_val, right_val)
|
||||
left_node_val = self.left.val if self.left else None
|
||||
right_node_val = self.right.val if self.right else None
|
||||
return "<TreeNode: {}, leftTreeNode: {}, rightTreeNode: {}>".format(val, left_node_val, right_node_val)
|
||||
|
||||
__repr__ = __str__
|
||||
```
|
||||
|
||||
=== "Go"
|
||||
@ -125,31 +122,17 @@ G. M. Adelson-Velsky 和 E. M. Landis 在其 1962 年发表的论文 "An algorit
|
||||
=== "Python"
|
||||
|
||||
```python title="avl_tree.py"
|
||||
def height(node: typing.Optional[AVLTreeNode]) -> int:
|
||||
"""
|
||||
获取结点高度
|
||||
Args:
|
||||
node:起始结点
|
||||
|
||||
Returns: 高度 or -1
|
||||
|
||||
"""
|
||||
""" 获取结点高度 """
|
||||
def height(self, node: typing.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
|
||||
|
||||
def update_height(node: AVLTreeNode):
|
||||
"""
|
||||
更新结点高度
|
||||
Args:
|
||||
node: 要更新高度的结点
|
||||
|
||||
Returns: None
|
||||
|
||||
"""
|
||||
""" 更新结点高度 """
|
||||
def __update_height(self, node: TreeNode):
|
||||
# 结点高度等于最高子树高度 + 1
|
||||
node.height = max([height(node.left), height(node.right)]) + 1
|
||||
node.height = max([self.height(node.left), self.height(node.right)]) + 1
|
||||
```
|
||||
|
||||
=== "Go"
|
||||
@ -207,20 +190,13 @@ G. M. Adelson-Velsky 和 E. M. Landis 在其 1962 年发表的论文 "An algorit
|
||||
=== "Python"
|
||||
|
||||
```python title="avl_tree.py"
|
||||
def balance_factor(node: AVLTreeNode) -> int:
|
||||
"""
|
||||
获取结点平衡因子
|
||||
Args:
|
||||
node: 要获取平衡因子的结点
|
||||
|
||||
Returns: 平衡因子
|
||||
|
||||
"""
|
||||
""" 获取平衡因子 """
|
||||
def balance_factor(self, node: TreeNode) -> int:
|
||||
# 空结点平衡因子为 0
|
||||
if node is None:
|
||||
return 0
|
||||
# 结点平衡因子 = 左子树高度 - 右子树高度
|
||||
return height(node.left) - height(node.right)
|
||||
return self.height(node.left) - self.height(node.right)
|
||||
```
|
||||
|
||||
=== "Go"
|
||||
@ -309,15 +285,16 @@ AVL 树的独特之处在于「旋转 Rotation」的操作，其可 **在不影
|
||||
=== "Python"
|
||||
|
||||
```python title="avl_tree.py"
|
||||
def rightRotate(node: AVLTreeNode):
|
||||
""" 右旋操作 """
|
||||
def __right_rotate(self, node: TreeNode) -> TreeNode:
|
||||
child = node.left
|
||||
grand_child = child.right
|
||||
# 以 child 为原点，将 node 向右旋转
|
||||
child.right = node
|
||||
node.left = grand_child
|
||||
# 更新结点高度
|
||||
update_height(node)
|
||||
update_height(child)
|
||||
self.__update_height(node)
|
||||
self.__update_height(child)
|
||||
# 返回旋转后子树的根节点
|
||||
return child
|
||||
```
|
||||
@ -387,15 +364,16 @@ AVL 树的独特之处在于「旋转 Rotation」的操作，其可 **在不影
|
||||
=== "Python"
|
||||
|
||||
```python title="avl_tree.py"
|
||||
def leftRotate(node: AVLTreeNode):
|
||||
""" 左旋操作 """
|
||||
def __left_rotate(self, node: TreeNode) -> TreeNode:
|
||||
child = node.right
|
||||
grand_child = child.left
|
||||
# 以 child 为原点，将 node 向左旋转
|
||||
child.left = node
|
||||
node.right = grand_child
|
||||
# 更新结点高度
|
||||
update_height(node)
|
||||
update_height(child)
|
||||
self.__update_height(node)
|
||||
self.__update_height(child)
|
||||
# 返回旋转后子树的根节点
|
||||
return child
|
||||
```
|
||||
@ -506,35 +484,28 @@ AVL 树的独特之处在于「旋转 Rotation」的操作，其可 **在不影
|
||||
=== "Python"
|
||||
|
||||
```python title="avl_tree.py"
|
||||
def rotate(node: AVLTreeNode):
|
||||
"""
|
||||
执行旋转操作，使该子树重新恢复平衡
|
||||
Args:
|
||||
node: 要旋转的根结点
|
||||
|
||||
Returns: 旋转后的根结点
|
||||
|
||||
"""
|
||||
""" 执行旋转操作，使该子树重新恢复平衡 """
|
||||
def __rotate(self, node: TreeNode) -> TreeNode:
|
||||
# 获取结点 node 的平衡因子
|
||||
factor = balance_factor(node)
|
||||
balance_factor = self.balance_factor(node)
|
||||
# 左偏树
|
||||
if factor > 1:
|
||||
if balance_factor(node.left) >= 0:
|
||||
if balance_factor > 1:
|
||||
if self.balance_factor(node.left) >= 0:
|
||||
# 右旋
|
||||
return right_rotate(node)
|
||||
return self.__right_rotate(node)
|
||||
else:
|
||||
# 先左旋后右旋
|
||||
node.left = left_rotate(node.left)
|
||||
return right_rotate(node)
|
||||
node.left = self.__left_rotate(node.left)
|
||||
return self.__right_rotate(node)
|
||||
# 右偏树
|
||||
elif factor < -1:
|
||||
if balance_factor(node.right) <= 0:
|
||||
elif balance_factor < -1:
|
||||
if self.balance_factor(node.right) <= 0:
|
||||
# 左旋
|
||||
return left_rotate(node)
|
||||
return self.__left_rotate(node)
|
||||
else:
|
||||
# 先右旋后左旋
|
||||
node.right = right_rotate(node.right)
|
||||
return left_rotate(node)
|
||||
node.right = self.__right_rotate(node.right)
|
||||
return self.__left_rotate(node)
|
||||
# 平衡树，无需旋转，直接返回
|
||||
return node
|
||||
```
|
||||
@ -611,42 +582,27 @@ AVL 树的独特之处在于「旋转 Rotation」的操作，其可 **在不影
|
||||
=== "Python"
|
||||
|
||||
```python title="avl_tree.py"
|
||||
def insert(val) -> AVLTreeNode:
|
||||
"""
|
||||
插入结点
|
||||
Args:
|
||||
val: 结点的值
|
||||
""" 插入结点 """
|
||||
def insert(self, val) -> TreeNode:
|
||||
self.root = self.__insert_helper(self.root, val)
|
||||
return self.root
|
||||
|
||||
Returns:
|
||||
node: 插入结点后的根结点
|
||||
"""
|
||||
root = insert_helper(root, val)
|
||||
return root
|
||||
|
||||
def insert_helper(node: typing.Optional[AVLTreeNode], val: int) -> AVLTreeNode:
|
||||
"""
|
||||
递归插入结点（辅助函数）
|
||||
Args:
|
||||
node: 要插入的根结点
|
||||
val: 要插入的结点的值
|
||||
|
||||
Returns: 插入结点后的根结点
|
||||
|
||||
"""
|
||||
""" 递归插入结点（辅助函数）"""
|
||||
def __insert_helper(self, node: typing.Optional[TreeNode], val: int) -> TreeNode:
|
||||
if node is None:
|
||||
return AVLTreeNode(val)
|
||||
return TreeNode(val)
|
||||
# 1. 查找插入位置，并插入结点
|
||||
if val < node.val:
|
||||
node.left = insert_helper(node.left, val)
|
||||
node.left = self.__insert_helper(node.left, val)
|
||||
elif val > node.val:
|
||||
node.right = insert_helper(node.right, val)
|
||||
node.right = self.__insert_helper(node.right, val)
|
||||
else:
|
||||
# 重复结点不插入，直接返回
|
||||
return node
|
||||
# 更新结点高度
|
||||
update_height(node)
|
||||
self.__update_height(node)
|
||||
# 2. 执行旋转操作，使该子树重新恢复平衡
|
||||
return rotate(node)
|
||||
return self.__rotate(node)
|
||||
```
|
||||
|
||||
=== "Go"
|
||||
@ -743,35 +699,20 @@ AVL 树的独特之处在于「旋转 Rotation」的操作，其可 **在不影
|
||||
=== "Python"
|
||||
|
||||
```python title="avl_tree.py"
|
||||
def remove(val: int):
|
||||
"""
|
||||
删除结点
|
||||
Args:
|
||||
val: 要删除的结点的值
|
||||
|
||||
Returns:
|
||||
|
||||
"""
|
||||
root = remove_helper(root, val)
|
||||
""" 删除结点 """
|
||||
def remove(self, val: int):
|
||||
root = self.__remove_helper(self.root, val)
|
||||
return root
|
||||
|
||||
def remove_helper(node: typing.Optional[AVLTreeNode], val: int) -> typing.Optional[AVLTreeNode]:
|
||||
"""
|
||||
递归删除结点（辅助函数）
|
||||
Args:
|
||||
node: 删除的起始结点
|
||||
val: 要删除的结点的值
|
||||
|
||||
Returns: 删除目标结点后的起始结点
|
||||
|
||||
"""
|
||||
""" 递归删除结点（辅助函数） """
|
||||
def __remove_helper(self, node: typing.Optional[TreeNode], val: int) -> typing.Optional[TreeNode]:
|
||||
if node is None:
|
||||
return None
|
||||
# 1. 查找结点，并删除之
|
||||
if val < node.val:
|
||||
node.left = remove_helper(node.left, val)
|
||||
node.left = self.__remove_helper(node.left, val)
|
||||
elif val > node.val:
|
||||
node.right = remove_helper(node.right, val)
|
||||
node.right = self.__remove_helper(node.right, val)
|
||||
else:
|
||||
if node.left is None or node.right is None:
|
||||
child = node.left or node.right
|
||||
@ -781,18 +722,17 @@ AVL 树的独特之处在于「旋转 Rotation」的操作，其可 **在不影
|
||||
# 子结点数量 = 1 ，直接删除 node
|
||||
else:
|
||||
node = child
|
||||
else: # 子结点数量 = 2 ，则将中序遍历的下个结点删除，并用该结点替换当前结点
|
||||
temp = min_node(node.right)
|
||||
node.right = remove_helper(node.right, temp.val)
|
||||
else: # 子结点数量 = 2 ，则将中序遍历的下个结点删除，并用该结点替换当前结点
|
||||
temp = self.min_node(node.right)
|
||||
node.right = self.__remove_helper(node.right, temp.val)
|
||||
node.val = temp.val
|
||||
# 更新结点高度
|
||||
update_height(node)
|
||||
self.__update_height(node)
|
||||
# 2. 执行旋转操作，使该子树重新恢复平衡
|
||||
return rotate(node)
|
||||
return self.__rotate(node)
|
||||
|
||||
|
||||
def min_node(node: typing.Optional[AVLTreeNode]) -> typing.Optional[AVLTreeNode]:
|
||||
# 获取最小结点
|
||||
""" 获取最小结点 """
|
||||
def min_node(self, node: typing.Optional[TreeNode]) -> typing.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
|
||||
|
||||
@ -82,11 +82,9 @@ comments: true
|
||||
=== "Python"
|
||||
|
||||
```python title="binary_search_tree.py"
|
||||
def search(self, num):
|
||||
"""
|
||||
查找结点
|
||||
"""
|
||||
cur = self.get_root()
|
||||
""" 查找结点 """
|
||||
def search(self, num: int) -> typing.Optional[TreeNode]:
|
||||
cur = self.root
|
||||
# 循环查找，越过叶结点后跳出
|
||||
while cur is not None:
|
||||
# 目标结点在 root 的右子树中
|
||||
@ -99,7 +97,6 @@ comments: true
|
||||
else:
|
||||
break
|
||||
return cur
|
||||
|
||||
```
|
||||
|
||||
=== "Go"
|
||||
@ -245,11 +242,9 @@ comments: true
|
||||
=== "Python"
|
||||
|
||||
```python title="binary_search_tree.py"
|
||||
def insert(self, num):
|
||||
"""
|
||||
插入结点
|
||||
"""
|
||||
root = self.get_root()
|
||||
""" 插入结点 """
|
||||
def insert(self, num: int) -> typing.Optional[TreeNode]:
|
||||
root = self.root
|
||||
# 若树为空，直接提前返回
|
||||
if root is None:
|
||||
return None
|
||||
@ -530,15 +525,13 @@ comments: true
|
||||
=== "Python"
|
||||
|
||||
```python title="binary_search_tree.py"
|
||||
def remove(self, num):
|
||||
"""
|
||||
删除结点
|
||||
"""
|
||||
root = self.get_root()
|
||||
""" 删除结点 """
|
||||
def remove(self, num: int) -> typing.Optional[TreeNode]:
|
||||
root = self.root
|
||||
# 若树为空，直接提前返回
|
||||
if root is None:
|
||||
return None
|
||||
|
||||
|
||||
cur = root
|
||||
pre = None
|
||||
|
||||
@ -574,13 +567,11 @@ comments: true
|
||||
# 递归删除结点 nex
|
||||
self.remove(nex.val)
|
||||
# 将 nex 的值复制给 cur
|
||||
cur.val = tmp
|
||||
cur.val = tmp
|
||||
return cur
|
||||
|
||||
def min(self, root):
|
||||
"""
|
||||
获取最小结点
|
||||
"""
|
||||
""" 获取最小结点 """
|
||||
def min(self, root: typing.Optional[TreeNode]) -> typing.Optional[TreeNode]:
|
||||
if root is None:
|
||||
return root
|
||||
|
||||
|
||||
@ -33,12 +33,19 @@ comments: true
|
||||
=== "Python"
|
||||
|
||||
```python title=""
|
||||
""" 链表结点类 """
|
||||
class TreeNode:
|
||||
""" 链表结点类 """
|
||||
def __init__(self, val=None, left=None, right=None):
|
||||
self.val = val # 结点值
|
||||
self.left = left # 左子结点指针
|
||||
self.right = right # 右子结点指针
|
||||
|
||||
def __str__(self):
|
||||
val = self.val
|
||||
left_node_val = self.left.val if self.left else None
|
||||
right_node_val = self.right.val if self.right else None
|
||||
return "<TreeNode: {}, leftTreeNode: {}, rightTreeNode: {}>".format(val, left_node_val, right_node_val)
|
||||
|
||||
```
|
||||
|
||||
=== "Go"
|
||||
@ -423,7 +430,8 @@ comments: true
|
||||
=== "Python"
|
||||
|
||||
```python title="binary_tree_bfs.py"
|
||||
def hierOrder(root):
|
||||
""" 层序遍历 """
|
||||
def hier_order(root):
|
||||
# 初始化队列，加入根结点
|
||||
queue = collections.deque()
|
||||
queue.append(root)
|
||||
@ -612,42 +620,36 @@ comments: true
|
||||
=== "Python"
|
||||
|
||||
```python title="binary_tree_dfs.py"
|
||||
def preOrder(root):
|
||||
"""
|
||||
前序遍历二叉树
|
||||
"""
|
||||
""" 前序遍历二叉树 """
|
||||
def pre_order(root: typing.Optional[TreeNode]):
|
||||
if root is None:
|
||||
return
|
||||
|
||||
|
||||
# 访问优先级：根结点 -> 左子树 -> 右子树
|
||||
result.append(root.val)
|
||||
preOrder(root=root.left)
|
||||
preOrder(root=root.right)
|
||||
pre_order(root=root.left)
|
||||
pre_order(root=root.right)
|
||||
|
||||
|
||||
def inOrder(root):
|
||||
"""
|
||||
中序遍历二叉树
|
||||
"""
|
||||
""" 中序遍历二叉树 """
|
||||
def in_order(root: typing.Optional[TreeNode]):
|
||||
if root is None:
|
||||
return
|
||||
|
||||
# 访问优先级：左子树 -> 根结点 -> 右子树
|
||||
inOrder(root=root.left)
|
||||
in_order(root=root.left)
|
||||
result.append(root.val)
|
||||
inOrder(root=root.right)
|
||||
in_order(root=root.right)
|
||||
|
||||
|
||||
def postOrder(root):
|
||||
"""
|
||||
后序遍历二叉树
|
||||
"""
|
||||
""" 后序遍历二叉树 """
|
||||
def post_order(root: typing.Optional[TreeNode]):
|
||||
if root is None:
|
||||
return
|
||||
|
||||
|
||||
# 访问优先级：左子树 -> 右子树 -> 根结点
|
||||
postOrder(root=root.left)
|
||||
postOrder(root=root.right)
|
||||
post_order(root=root.left)
|
||||
post_order(root=root.right)
|
||||
result.append(root.val)
|
||||
```
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user