length = 0
while head:
head = head.next
length += 1
step = 1
while step < length:
prev = dummy
curr = dummy.next
while curr:
left = curr
right = split(left, step)
curr = split(right, step)
prev = merge(left, right, prev)
step *= 2
return dummy.next
if __name__ == '__main__':
s = Solution()
head = ListNode.from_list([4, 2, 1, 3])
ans = s.sortList(head)
print(ans.show())
head = ListNode.from_list([-1, 5, 3, 4, 0])
ans = s.sortList2(head)
print(ans.show())
sys.path.append("..")
from typing import Optional
from utils import ListNode
class Solution:
def swapPairs(self, head: Optional[ListNode]) -> Optional[ListNode]:
n = ListNode(val=None, next=head)
slow, fast = n, n.next
while fast and fast.next:
slow.next = fast.next
temp = fast.next.next
fast.next.next = fast
fast.next = temp
slow = fast
fast = fast.next
return n.next
if __name__ == '__main__':
s = Solution()
head = ListNode.from_list([1, 2, 3, 4])
ans = s.swapPairs(head)
print(ans.show())
class Solution:
def deleteDuplicates(self, head: Optional[ListNode]) -> Optional[ListNode]:
n = ListNode(val=float("-inf"), next=head)
slow, fast = n, head
last = n.val
while fast:
if fast.next and fast.val == fast.next.val:
last = fast.val
fast = fast.next.next
elif last == fast.val:
fast = fast.next
else:
slow.next = fast
slow = slow.next
fast = fast.next
slow.next = fast
return n.next
if __name__ == '__main__':
s = Solution()
head = ListNode.from_list([1, 2, 3, 3, 4, 4, 5])
ans = s.deleteDuplicates(head)
print(ans.show())
