leetcode——101. 对称二叉树

class Solution(object):
    def isSymmetric(self, root):
        """
        :type root: TreeNode
        :rtype: bool
        """
        if not root:return True
        def Tree(p,q):
            if not p and not q:return True
            if p and q and p.val==q.val:
                return Tree(p.left,q.right) and Tree(p.right,q.left)
            return False
        return Tree(root.left,root.right)