RT

int n;
struct node
{
    int key;
    node* next;
    node* prev;
};
int main()
{
    node* p;
    node* h = new node;
    node* r = new node;
    h -> next = NULL;
    r -> next = NULL;
    h -> prev = NULL;
    r -> prev = NULL;
    cin >> n;
    while(n--)
    {
        p = new node;
        cin >> p -> key;
        node* q = r;
        while(q -> prev != NULL && q -> key < p -> key)
        	q = q -> prev;
//        if(q -> prev == NULL)
//        	h = p;
//        if(q -> next == NULL)
//        	r = p;
//        p -> next = q -> next;
//        q -> next -> prev = p;
    }
    while(h -> next != NULL)
    {
        cout << h -> key << " ";
        h = h -> next;
    }
    return 0;
}

蒟蒻刚学链表，请问这个链表插入排序的头尾指针如何更新？