题目：Given a linked list, remove thenthnode from the end of list and return its head.
For example：
Given linked list: 1->2->3->4->5, and n = 2.
After removing the second node from the end, the linked list becomes 1->2->3->5.
struct ListNode {int val;ListNode *next;ListNode(int x) : val(x), next(NULL) {}};ListNode *removeNthFromEnd(ListNode *head, int n){ListNode *r = head, *s;if (head == NULL)return head;int i = 0;for (ListNode *p = head; p != NULL; p = p->next){i++; }if (i == n) //删除第一个节点{ListNode *l = head->next;free(head);return l;}for (int num = 0; num < i – n – 1; num++)//找到要删节点的前一个节点{r = r->next;}ListNode *tmp = r->next;r->next = r->next->next;free(tmp);return head;}
，生命太过短暂，今天放弃了明天不一定能得到
