题解 | #删除链表的倒数第n个节点#

package main

import . "nc_tools"
/*
 * type ListNode struct{
 *   Val int
 *   Next *ListNode
 * }
 */

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param head ListNode类 
 * @param n int整型 
 * @return ListNode类
*/
func removeNthFromEnd( head *ListNode ,  n int ) *ListNode {
    // write code here

    virtual := &ListNode{}
    virtual.Next = head

    pre := virtual
    fast := head
    slow := head

    for i := 0;i<n;i++ {
        fast = fast.Next
    }

    for i:=0;;i++ {
        if fast == nil {
            break
        }
        pre = pre.Next
        fast = fast.Next
        slow = slow.Next 
    }
    pre.Next = slow.Next
    return virtual.Next

}