二叉树的高度：左右两个数最高的那个的+1

int TreeHight(BTNode* root)
{
	if (root == NULL)
	{
		return 0;
	}
	int lefhight=TreeHight(root->left);
	int righthight = TreeHight(root->right);

	return lefhight > righthight ? TreeHight(root->left) + 1 : TreeHight(root->right) + 1;
}