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。

 1 /*
 2 struct ListNode {
 3     int val;
 4     struct ListNode *next;
 5     ListNode(int x) :
 6             val(x), next(NULL) {
 7     }
 8 };*/
 9 class Solution {
10 public:
11     ListNode* FindKthToTail(ListNode* pListHead, unsigned int k) {
12         ListNode* p = pListHead,* pre = pListHead;
13         while(k-- && p != NULL)
14             p = p->next;
15         if (k!=-1)
16             return NULL;
17         while(p != NULL)
18             {
19                 p = p->next;
20                 pre = pre->next;
21             }
22         return pre;
23     }
24 };