题解 | #对称的二叉树#

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param pRoot TreeNode类 
# @return bool布尔型
#
class Solution:
    def isSymmetrical(self , pRoot: TreeNode) -> bool:
        if not pRoot:
            return True
        # write code here
        def compare( left,  right) -> bool:
            if not left and not right:
                return True


            if (not right and left) or (not left  and right):
                return False

            if left.val != right.val:
                return False


            if left.val == right.val:
                A = compare(left.right,right.left) 
                B = compare(left.left,right.right)
                return  A and B
            else:
                return False
            

        return compare(pRoot.left,pRoot.right)