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.
問題分析,n的取值可能爲1(刪除最後一個),5(刪除第一個),0(不刪除),6(無效刪除),因此我們添加一個頭nHead,並且使用尺寸爲n的滑動窗口,一邊掃描數據,刪除距離鏈表尾爲n的點
public class Solution {
public ListNode removeNthFromEnd(ListNode head, int n) {
ListNode nHead=new ListNode(0);
nHead.next=head;
ListNode first=nHead;
ListNode end=head;
int i=1;
while(i<n&&end.next!=null)
{
end=end.next;
i++;
}
if(i==n)
{
while(end.next!=null)
{
end=end.next;
first=first.next;
}
first.next=first.next.next;
}
return nHead.next;
}
}