删除链表的倒数第 N 个结点

// 使用Java Stream的题解代码和注释
// 思路：由于Java Stream不直接支持链表的处理，我们可以使用Stream进行辅助计算。首先将链表转化为列表，然后通过列表的操作来处理倒数第n个元素的删除，最后再转化回链表。
 
import java.util.List;
import java.util.ArrayList;
import java.util.stream.IntStream;
 
class ListNode {
    int val;
    ListNode next;
    ListNode(int x) { val = x; }
}
 
public class Solution {
    public ListNode removeNthFromEnd(ListNode head, int n) {
        List<ListNode> nodeList = new ArrayList<>();
        ListNode current = head;
        while (current != null) {
            nodeList.add(current);
            current = current.next;
        }
        int removeIndex = nodeList.size() - n;
        if (removeIndex == 0) {
            return head.next; // 删除头节点
        }
        ListNode previous = nodeList.get(removeIndex - 1);
        previous.next = previous.next.next;
        return head;
    }
}