对称二叉树

class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

def solve():
    def isSymmetric(root):
        def isMirror(left, right):
            if not left and not right:
                return True
            if not left or not right:
                return False
            return left.val == right.val and isMirror(left.left, right.right) and isMirror(left.right, right.left)
        return isMirror(root, root)
    root = TreeNode(1, TreeNode(2, TreeNode(3), TreeNode(4)), TreeNode(2, TreeNode(4), TreeNode(3)))
    print(isSymmetric(root))