输入一个链表，输出该链表中倒数第k个结点

输出该链表中倒数第k个结点

    ListNode* FindKthToTail(ListNode* pListHead, unsigned int k)     {        if(pListHead == NULL || k < 1)            return NULL;        ListNode *pAhead = pListHead;        ListNode *pBehind = NULL;        for(unsigned int i=0; i < k-1; ++i)        {            if(pAhead->next != NULL)                pAhead = pAhead->next;            else                return NULL;        }        pBehind = pListHead;        while(pAhead->next != NULL)        {            pAhead = pAhead->next;            pBehind = pBehind->next;        }        return pBehind;    }