题解 | #删除链表的倒数第n个节点#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param n int整型 
     * @return ListNode类
     */
    public ListNode removeNthFromEnd (ListNode head, int n) {
        ListNode cur=head;
        int len=0;
        while(cur!=null){
            len++;
            cur=cur.next;
        }
        int pos=len-n;
        if(pos==0){
            head=head.next;
            return head;
        }
        cur=head;
        ListNode prev=cur;
        for(int i=0;i<pos;i++){
            prev=cur;
            cur=cur.next;
        }
        prev.next=cur.next;
        
        return head;
    }
}