Remove Nth Node From End of List

Given a linked list, remove the n^th node from the end of list and return its head.
For example,

   Given linked list: 1->2->3->4->5, and n = 2.

   After removing the second node from the end, the linked list becomes 1->2->3->5.

Note:
Given n will always be valid.
Try to do this in one pass.

Solution:

class Solution {
public:
    ListNode *removeNthFromEnd(ListNode *head, int n) {

       ListNode  *fast , *slow;
       fast=slow=head;
       for(int i=0; inext;
       if (fast==NULL) return head->next;
       else{
           while(fast->next!=NULL){
               fast=fast->next;
               slow=slow->next;
           }
           slow->next=slow->next->next;
       }
       return head;
    }
};

Not much to explain here.