链表中倒数第k个结点

题目描述

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,* pre = pListHead;
        while(k-- && p != NULL)
            p = p->next;
        if (k!=-1)
            return NULL;
        while(p != NULL)
            {
                p = p->next;
                pre = pre->next;
            }
        return pre;
    }
};