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。
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
if(n==) return head;
int res=;
ListNode *p=head;
while(p){
res++;
p=p->next;
}
ListNode *k=new ListNode();
k->next=head;
head=k;
ListNode *q=head->next;
for(int i=;i<=res;i++){
if(res-i+==n){
k->next=q->next;
break;
}
k=q;
q=q->next;
}
head=head->next;
return head;
}
};