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) {
    	ListNode *p = pListHead;
        if(pListHead == NULL) return NULL;
        int cnt = 0;
		while(p){
            cnt++;
            p = p->next;
        }
        if(cnt<k) return NULL;
        for(int i =1;i<cnt-k+1;i++){
            pListHead = pListHead->next;
        }
        return pListHead;
    }
};