题目
给定一个链表,删除链表的倒数第 n 个节点,并且返回链表的头结点。
示例:
给定一个链表: 1->2->3->4->5, 和 n = 2.
当删除了倒数第二个节点后,链表变为 1->2->3->5.
题解
dummyNode ,双指针,fast先走N+1步。
代码
/**
* 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 dummyNode = new ListNode(-1);
dummyNode.next = head;
ListNode slow = dummyNode;
ListNode fast = dummyNode;
for (int i = 0; i < n + 1; ++i) {
fast = fast.next;
}
while (fast != null) {
fast = fast.next;
slow = slow.next;
}
slow.next = slow.next.next;
return dummyNode.next;
}
}
,