迭代树序列化函数

class TreeNode:
    def __init__(self, value=0, left=None, right=None):
        self.value = value
        self.left = left
        self.right = right

def serialize(root):
    if not root:
        return []
    
    stack = [root]
    result = []
    
    while stack:
        node = stack.pop()
        if node:
            result.append(node.value)
            stack.append(node.right)
            stack.append(node.left)
        else:
            result.append(None)
    
    return result

def deserialize(data):
    if not data:
        return None
    
    root = TreeNode(data[0])
    stack = [root]
    index = 1
    
    while stack and index < len(data):
        node = stack.pop()
        
        if data[index] is not None:
            node.left = TreeNode(data[index])
            stack.append(node.left)
        index += 1
        
        if index < len(data) and data[index] is not None:
            node.right = TreeNode(data[index])
            stack.append(node.right)
        index += 1
    
    return root

# 示例用法
root = TreeNode(1, TreeNode(2), TreeNode(3, TreeNode(4), TreeNode(5)))
serialized_data = serialize(root)
print("Serialized:", serialized_data)

deserialized_root = deserialize(serialized_data)
print("Deserialized root value:", deserialized_root.value)