Given a linked list, remove the nth
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.
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
public class Solution {
public ListNode removeNthFromEnd(ListNode head, int n) {
if(head == null)
return null;
ListNode dummy = new ListNode(0);
dummy.next = head;
ListNode p = dummy;
ListNode q = dummy;
for(int i=0;i<n;i++)
{
p = p.next;
if(p==null)
return null;
}
while(p.next!=null)
{
p = p.next;
q = q.next;
}
q.next = q.next.next;
return dummy.next;
}
}
