## Problem

Given a sorted linked list, delete all duplicates such that each element appear only

*once*.For example,

Given

Given

Given

`1->1->2`

, return `1->2`

.Given

`1->1->2->3->3`

, return `1->2->3`

.## Analysis

- Use pointer operation
- If next element is repeated, then
- curr.next = curr.next.next
- Else
- curr = curr.next