解题思路:
快慢指针
class Solution {public ListNode removeNthFromEnd(ListNode head, int n) {ListNode dummy = new ListNode(-1);dummy.next = head;ListNode fast = dummy;ListNode slow = dummy;for (int i = 0; i < n; i++) {fast = fast.next;}while (fast.next != null) {fast = fast.next;slow = slow.next;}slow.next = slow.next.next;return dummy.next;}
}