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; }
* }
*/
class Solution {
public ListNode removeNthFromEnd(ListNode head, int n) {
ListNode newList = new ListNode(0); //头结点
newList.next = head;
ListNode tmp =head;
ListNode pre = newList;
int i = n;
while (i>1){
head = head.next;
i--;
}
while (head.next!=null){
head = head.next;
pre = pre.next;
}
pre.next = pre.next.next;
return newList.next;
}
}