博客

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def isSymmetric(self, root: TreeNode) -> bool:
        if root== None:
            return True
        else:
            return recurse(root.left,root.right)
         
def recurse(leftNode,rightNode):
        if leftNode == None and rightNode == None:
            return True
        elif leftNode != None and rightNode != None:
            if leftNode.val ==rightNode.val:
                return recurse(leftNode.left,rightNode.right) and recurse(leftNode.right,rightNode.left)
            else:
                return False
        else:
            return False