剑指offer（C++）--链表中倒数第k个结点

题目

输入一个链表，输出该链表中倒数第k个结点。

/*
struct ListNode {
	int val;
	struct ListNode *next;
	ListNode(int x) :
			val(x), next(NULL) {
	}
};*/
class Solution {
public:
    ListNode* FindKthToTail(ListNode* pListHead, unsigned int k) {
       if(pListHead == nullptr || k == 0)
          return nullptr;
       ListNode * pAhead = pListHead;
       ListNode * pBahead = nullptr;
        for(unsigned int i = 0; i < k - 1; i++)
        {
            if(pAhead->next != nullptr){
                 pAhead = pAhead->next;
            }
            else
            {
                return nullptr;
            }
        }
        pBahead = pListHead;
        while(pAhead->next != nullptr)
        {
            pAhead = pAhead->next;
            pBahead = pBahead->next;
        }
        return pBahead;
    }
};