def deleteDuplicates(self, head: ListNode) -> ListNode:
dummy = ListNode(0)
prev = dummy
dummy.next = head
while head and head.next:
if head.val == head.next.val:
while head.next and head.val == head.next.val:
head = head.next
head = head.next
prev.next = head
else:
prev = prev.next
head = head.next
return dummy.next
def reverseBetween(self, head: ListNode, m: int, n: int) -> ListNode:
if m == n:
return head
n -= m - 1
dummy = ListNode(0)
tail1, dummy.next = dummy, head
for _ in range(m - 1):
tail1, head = head, head.next
tail2, head, tail1.next = head, head.next, head
for _ in range(n - 1):
head.next, tail1.next, head = tail1.next, head, head.next
tail2.next = head
return dummy.next
def insertionSortList(self, head: ListNode) -> ListNode:
dummy = ListNode(0)
dummy.next = head
prev = dummy
current = dummy.next
while current:
nprev = dummy
node = nprev.next
while node != current and node.val <= current.val:
nprev = node
node = node.next
if node != current:
prev.next = current.next
current.next = node
nprev.next = current
else:
prev = current
current = prev.next
return dummy.next