[剑指offer] 14. 链表中倒数第k个结点

class Solution
{
public:
  ListNode *FindKthToTail(ListNode *pListHead, unsigned int k)
  {
    if (pListHead == NULL)
      return NULL;
    ListNode *low = pListHead;
    ListNode *high = pListHead;

    for (int i = 0; i < k - 1; i++)
    {
      if (high->next == NULL)
        return NULL;
      high = high->next;
    }

    while (high->next != NULL)
    {
      high = high->next;
      low = low->next;
    }
    return low;
  }
};