自定义类实现二叉树，python完整代码

在Python中，我们可以自定义一个类来实现二叉树。以下是一个简单的二叉树类，包括节点的创建、插入和基本的遍历（前序、中序和后序）：

class Node:
    def __init__(self, value):
        self.value = value
        self.left = None
        self.right = None

class BinaryTree:
    def __init__(self):
        self.root = None

    def insert(self, value):
        if not self.root:
            self.root = Node(value)
        else:
            self._insert(self.root, value)

    def _insert(self, node, value):
        if value < node.value:
            if node.left is None:
                node.left = Node(value)
            else:
                self._insert(node.left, value)
        else:
            if node.right is None:
                node.right = Node(value)
            else:
                self._insert(node.right, value)

    # 前序遍历 (根-左-右)
    def pre_order_traversal(self, node=None):
        if node is None:
            node = self.root
        if node:
            print(node.value, end=" -> ")
            self.pre_order_traversal(node.left)
            self.pre_order_traversal(node.right)

    # 中序遍历 (左-根-右)
    def in_order_traversal(self, node=None):
        if node is None:
            node = self.root
        if node:
            self.in_order_traversal(node.left)
            print(node.value, end=" -> ")
            self.in_order_traversal(node.right)

    # 后序遍历 (左-右-根)
    def post_order_traversal(self, node=None):
        if node is None:
            node = self.root
        if node:
            self.post_order_traversal(node.left)
            self.post_order_traversal(node.right)
            print(node.value, end=" -> ")

# 示例
tree = BinaryTree()
tree.insert(5)
tree.insert(3)
tree.insert(7)
tree.insert(2)
tree.insert(4)
tree.insert(6)
tree.insert(8)

# 遍历
print("前序遍历:")
tree.pre_order_traversal()
print("\n中序遍历:")
tree.in_order_traversal()
print("\n后序遍历:")
tree.post_order_traversal()