删除链表的倒数第 n 个节点
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.
public ListNode removeNthFromEnd(ListNode head, int n) {
ListNode dummy = new ListNode(0);
dummy.next = head;
ListNode l1 = dummy;
ListNode l2 = dummy;
while(l2 != null){
if(n < 0){
l1 = l1.next;
}
l2 = l2.next;
n--;
}
l1.next = l1.next.next;
return dummy.next;
}
