力扣19 删除链表的第N个结点

class Solution {
public:
    ListNode* removeNthFromEnd(ListNode* head, int n) {
        int length=0;
        ListNode* result=new ListNode();
        ListNode* cur =head;
        result=cur;
        while(cur!=NULL)
        {
            length++;
            cur=cur->next;
        }
        cur=head;
        if((length-n)==0) return cur->next;
        for(int i=0;i<length-n-1;i++) 
        {
           cur=cur->next;
        }
        cur->next=cur->next->next;
        return result;
    }
};