【leetcode】对称的二叉树

bool judge(struct TreeNode* left_node, struct TreeNode* right_node)
{
    if (left_node == NULL && right_node == NULL)
        return true;
    else if (left_node == NULL || right_node == NULL)
        return false;
    if (left_node->val != right_node->val)
        return false;
    return judge(left_node->left, right_node->right) && judge(left_node->right, right_node->left);
}
bool isSymmetric(struct TreeNode* root){
    if (root == NULL)
        return true;
    return judge(root->left, root->right);
}