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(-1);
        fake->next = head;
        ListNode* p = fake;
        while(n >0){
            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;
    }
};