def qucik_sort_list(head):
def partition(start, end):
node = start.next.next
pivotPrev = start.next
pivotPrev.next = end
pivotPost = pivotPrev
while node != end:
temp = node.next
if node.val > pivotPrev.val:
node.next = pivotPost.next
pivotPost.next = node
elif node.val < pivotPrev.val:
node.next = start.next
start.next = node
else:
node.next = pivotPost.next
pivotPost.next = node
pivotPost = pivotPost.next
node = temp
return [pivotPrev, pivotPost]
def quicksort(start, end):
if start.next != end:
prev, post = partition(start, end)
quicksort(start, prev)
quicksort(post, end)
newHead = ListNode(0)
newHead.next = head
quicksort(newHead, None)
return newHead.next
def reverse(p):
newHead = ListNode('')
while p:
q = p
p = p.next
q.next = newHead.next
newHead.next = q
return newHead.next
def mergesort_List(head: ListNode) -> ListNode:
def merge(head, q, qk, k):
left = right = k
while left and right and qk:
if q.val > qk.val:
head.next = qk
qk = qk.next
right -= 1
else:
head.next = q
q = q.next
left -= 1
head = head.next
head.next = None
while left and q:
head.next = q
q = q.next
head = head.next
left -= 1
while right and qk:
head.next = qk
qk = qk.next
right -= 1
head = head.next
head.next = qk
return head
k, length = 1, 0
p = head
while p:
length += 1
p = p.next
newHead = ListNode('')
newHead.next = head
while k < length:
head = newHead
while head.next:
q = qk = head.next
for i in range(k):
if not qk:
break
qk = qk.next
head = merge(head, q, qk, k)
k *= 2
return newHead.next