leetcode 19 Remove Nth Node From End of List C++

注意特殊的地方，就是第一个节点被去掉了。

    ListNode* removeNthFromEnd(ListNode* head, int n) {
        ListNode *fast = head;
        ListNode *slow = head;
        
        while(n--){
            fast = fast->next;
        }
        
        if(!fast) return head->next;
        
        while(fast->next){
            fast = fast->next;
            slow = slow->next;
        }
        slow->next = slow->next->next;
        return head;
        
        
    }