/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    int Length(ListNode *l) {
			int count = 0;
			ListNode *p = l;
			while (p != NULL) {
				count++;
				p = p->next;
			}
			return count;
		}

	ListNode* removeNthFromEnd(ListNode* head, int n) {
			ListNode *pre_remove = head, *remove;
			int length = Length(head);
			if (length - n == 0) {
				return pre_remove->next;
			}
			int flg = 1;
			while (flg < length - n) {
				pre_remove = pre_remove->next;
				flg++;
			}

			remove = pre_remove->next;
			pre_remove->next = remove->next;
			remove = NULL;
			return head;
		}
};