Given a sorted linked list, delete all duplicates such that each element appear only once.
Input: 1->1->2 Output: 1->2
Input: 1->1->2->3->3 Output: 1->2->3
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def deleteDuplicates(self, head: ListNode) -> ListNode:
cur = head
while cur and cur.next:
if cur.val == cur.next.val:
cur.next = cur.next.next
else:
cur = cur.next
return head