寻找链表中倒数第K个结点的位置

1 struct ListNode
2 {
3     int m_nValue;
4     ListNode* m_pNext;
5 };
6 ListNode* FindKthToTail(ListNode* pListHead , unsigned int K)
7 {
8     if (!pListHead || K <=0)
9     {
10         return NULL ;
11     }
12     ListNode* pAhead = pListHead;
13     ListNode* pBehind = NULL ;
14     for (int i=1 ; i != K ;i++)
15     {
16         if (pAhead->m_pNext != NULL)
17         {
18             pAhead = pAhead->m_pNext ;
19         }
20         else
21         {
22             return NULL;
23         }
24     }
25     pBehind = pListHead ;
26     while(pAhead->m_pNext != NULL)
27     {
28         pAhead = pAhead->m_pNext ;
29         pBehind = pBehind->m_pNext;
30     }
31     return pBehind ;
32 }