面试题28：单链表一次遍历删除从后往前的第n个节点

 class Solution {
 public:
     ListNode *removeNthFromEnd(ListNode *head, int n) {

         ListNode* fake = new ListNode(-);
         fake->next = head;
         ListNode* p = fake;
         while(n >){
             p = p->next;
             n--;
         }

         ListNode* cur = fake;
         while(p->next){
             p = p->next;
             cur = cur->next;
         }
         ListNode* tmp = cur->next;
         cur->next = cur->next->next;
         delete tmp;

         return fake->next;
     }
 };