剑指offer-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* ph = pListHead, *pf = pListHead;
        for(int i = 0; ph && i < k - 1; ++i){
            ph = ph->next;
        }
        if(ph == nullptr)
            return nullptr;
        while(ph->next){
            ph = ph->next;
            pf = pf->next;
        }
        return pf;
    }
};