面试题13 在O(1)时间删除链表结点

typedef struct Node
{
    int elem;
    struct Node *next;
}*LinkList, node;

void Delete(LinkList *head, node *p) {
    if (!head || !p)
        return;
    if (p->next != NULL) {
        node *q = p->next;
        p->elem = q->elem;
        p->next = q->next;
        delete q;
        p = NULL;
        q = NULL;
    }
    else if (*head == p){
        delete p;
        p = NULL;
        *head = NULL;
    }
    else {
        node *q = *head;
        while (q->next->next != NULL) {
            q = q->next;
        }
        q->next = NULL;
        delete p;
        p = NULL;
    }
}