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 
 * @return ListNode类
*/
func deleteDuplicates( head *ListNode ) *ListNode {
    if head == nil {
        return head
    }
    r,l := head,head
    for r != nil {
        if r == l || r.Val == l.Val {
            r = r.Next
            continue
        }
        l.Next = r
        l = r
    }
    l.Next = r
    l = r
    return head
}