统计二叉树中度为0，1，2的节点个数

int NumsDegree_0(BiTree T)
{
	if(T)
	{
		if(T->left == NULL && T->right == NULL)
			return 1;
		else
			return NumsDegree_0(T->left)+NumsDegree_0(T->right);
	}
	else
		return 0;
}

int NumsDegree_1(BiTree T)
{
	if(T)
	{
		if((T->left && T->right==NULL) || (T->right && T->right==NULL))
			return NumsDegree_1(T->left) + NumsDegree_1(T->right) +1;
		else
			return NumsDegree_1(T->left) + NumsDegree_1(T->right);
	}
	else
		return 0;
}

int NumsDegree_2(BiTree T)
{
	if(T)
	{
		if(T->left && T->right)
			return NumsDegree_2(T->left) + NumsDegree_2(T->right) +1;
		else
			return NumsDegree_2(T->left) + NumsDegree_2(T->right);
	}
	else
		return 0;
}