Leedcode相同二叉树 Python先序遍历

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def isSameTree(self, p: TreeNode, q: TreeNode) -> bool:
        if not p and not q:return True
        if not p or not q:return False
        a=[]
        def pre_order(root):
            a.append(root.val)
            if root.left:
                pre_order(root.left)
            else:
                a.append(None)
            if root.right:
                pre_order(root.right)
            else:
                a.append(None)
            return a
        stack1=pre_order(p)
        a=[]
        stack2=pre_order(q)
        return True if stack1==stack2 else False