Remove Nth Node From End of List 删除链表的倒数第n个结点

/**

* Definition for singly-linked list.

* struct ListNode {

* int val;

* ListNode *next;

* ListNode(int x) : val(x), next(NULL) {}

* };

*/

class Solution {

public:

ListNode *removeNthFromEnd(ListNode *head, int n) {

ListNode dummy(-1);

dummy.next=head;

ListNode *prev=&dummy;

ListNode *p=head;

ListNode *q=head;

for(int i=0;i<n;i++)

{

p=p->next;

}

while(p!=NULL)

{

prev=q;

p=p->next;

q=q->next;

}

prev->next=q->next;

ListNode *temp=q;

delete q;

return dummy.next;

}

};