给定一个链表，删除链表中倒数第n个节点，返回链表的头节点。
注意事项
链表中的节点个数大于等于n
您在真实的面试中是否遇到过这个题？ Yes
样例
给出链表1->2->3->4->5->null和 n = 2.
删除倒数第二个节点之后，这个链表将变成1->2->3->5->null.
/**
* Definition of ListNode
* class ListNode {
* public:
* int val;
* ListNode *next;
* ListNode(int val) {
* this->val = val;
* this->next = NULL;
* }
* }
*/
class Solution {
public:
/**
* @param head: The first node of linked list.
* @param n: An integer.
* @return: The head of linked list.
*/
ListNode *removeNthFromEnd(ListNode *head, int n) {
// write your code here
ListNode* start = new ListNode(0);
start -> next = head;
ListNode* fast = start;
ListNode* slow = start;
int i = 1;
while(fast != NULL && i<=n) {
fast = fast->next;
i++;
}
while(fast->next != NULL) {
fast = fast->next;
slow = slow->next;
}
slow->next = slow->next->next;
return start -> next;
}
};
