应用题-二叉树专题-完全二叉树的节点个数
**写法1** ```python # Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.v
**写法1** ```python # Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.v