typedef struct BiTNode
{
	ElemType data;
	struct BiTNode *lchild,*rchild;
}BiTNode,*BiTree;
BiTNode *parent(BiTree T,ElemType x)
{
	BiTNode *ans;
	if(T==NULL)
		return NULL;
	if(T->lchild==NULL&&T->rchild==NULL)
	   return NULL
	else
	{
		if(T->lchild->data==x||T->rchild->data==x)
			return T;
		else
		{
			ans=parent(T->lchild,x);
			if(ans)
                return ans;
            ans=parent(T->rchild,x);
			if(ans)
                return ans;
            return NULL;

		}
	}
}