给定一个排序链表，删除所有含有重复数字的节点，只保留原始链表中 没有重复出现 的数字。
示例 1:
输入: 1->2->3->3->4->4->5
输出: 1->2->5
示例 2:
输入: 1->1->1->2->3
输出: 2->3
/**
* Definition for singly-linked list.
* type ListNode struct {
* Val int
* Next *ListNode
* }
*/
func deleteDuplicates(head *ListNode) *ListNode {
if head == nil {
return head
}
appear := make(map[int]int, 0)
before := head
current := head
for {
if current == nil {
break
}
if appear[current.Val] >= 1 {
appear[current.Val]++
next := current.Next
before.Next = next
current = next
} else {
appear[current.Val]++
before = current
current = current.Next
}
}
before = head
current = head
for {
if current == nil {
break
}
if appear[current.Val] > 1 {
next := current.Next
before.Next = next
current = next
} else {
before = current
current = current.Next
}
}
if appear[head.Val] > 1 {
return head.Next
}
return head
}
