Difficulty: Medium
Given a linked list, remove the n-th node from the end of list and return its head.
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.
Follow up:
Could you do this in one pass?
Language: Java
/**
* 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 node1 = head;
ListNode node2 = head;
// 由于题目中说到 n 永远有效，所以不做 nodeList 长度不足n的判断
for (int i = 0; i < n; i++) {
node1 = node1.next;
}
if (node1 == null) {
return head.next;
}
node1 = node1.next;
while (node1 != null) {
node1 = node1.next;
node2 = node2.next;
}
node2.next = node2.next.next;
return head;
}
}
node2 = node2.next;