Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
Return the linked list sorted as well.
Example 1:
Input: 1->2->3->3->4->4->5
Output: 1->2->5
Example 2:
Input: 1->1->1->2->3
Output: 2->3
class Solution:
def deleteDuplicates(self, head: ListNode) -> ListNode:
if not head or not head.next:
return head
extra = ListNode(None)
extra.next = head
pre = extra
while head and head.next:
if head.val == head.next.val:
while head and head.next and head.val == head.next.val:
head = head.next
head = head.next
pre.next = head
else:
pre = head
head = head.next
return extra.next