def reverseBetween(self, head, m, n):
#edge case
mnDiff = n - m
if mnDiff == 0:
return head
#find H and T
dummyHead = mylist.ListNode(0)
dummyHead.next = head
h = head
t = head
i = 0
while i < mnDiff:
t = t.next
i += 1
i = 1
pre = dummyHead
while i < m:
h = h.next
t = t.next
pre = pre.next
i += 1
#reverse
pre.next = t
one = h
two = h.next
three = two.next
h.next = t.next
while two != t:
two.next = one
one = two
two = three
if three != None:
three = three.next
two.next = one
return dummyHead.next
def partition(self, head, x):
#edge case
if head == None or head.next == None:
return head
dummyHead = mylist.ListNode(0)
dummyHead.next = None
bigTail = None
smallTail = dummyHead
smallTail.next = None
cursor = head
while cursor != None:
newCur = cursor.next
if cursor.val < x:
#append to small
cursor.next = smallTail.next
smallTail.next = cursor
smallTail = cursor
else:
#append to big
if smallTail.next == None:
smallTail.next = cursor
bigTail = cursor
else:
bigTail.next = cursor
bigTail = cursor
bigTail.next = None
cursor = newCur
return dummyHead.next
def addTwoNumbers(self, l1, l2):
c = 0
rvH = l1
if l1 == None:
return l2
elif l2 == None:
return l1
while True:
tmpRes = l1.val + l2.val + c
if tmpRes >= 10:
l1.val = tmpRes % 10
c = 1
else:
l1.val = tmpRes
c = 0
if l1.next != None and l2.next != None:
l1 = l1.next
l2 = l2.next
else:
break
if l2.next != None:
l1.next = l2.next
l2.next.val += c
l2 = l2.next
while l2.val == 10:
l2.val %= 10
if l2.next != None:
l2.next.val += 1
l2 = l2.next
else:
newNode = mylist.ListNode(1)
l2.next = newNode
elif l1.next != None:
l1.next.val += c
l1 = l1.next
while l1.val == 10:
l1.val %= 10
if l1.next != None:
l1.next.val += 1
l1 = l1.next
else:
newNode = mylist.ListNode(1)
l1.next = newNode
elif c == 1:
newNode = ListNode(1)
l1.next = newNode
return rvH
def swapPairs(self, head):
if head == None or head.next == None:
return head
dummyHead = mylist.ListNode(0)
pre = dummyHead
oneNode = head
while oneNode != None and oneNode.next != None:
twoNode = oneNode.next
#store next
newOne = twoNode.next
#swap
pre.next = twoNode
twoNode.next = oneNode
oneNode.next = None
#prepare for next
pre = oneNode
oneNode = newOne
if oneNode != None:
pre.next = oneNode
return dummyHead.next
def deleteDuplicates(self, head):
#edge case
if head == None or head.next == None:
return head
dummyHead = mylist.ListNode(0)
dummyHead.next = head
pre = dummyHead
anchor = head
cursor = head.next
while cursor != None:
if cursor.val != anchor.val:
if anchor.next == cursor:
pre = pre.next
pre.next = cursor
anchor = cursor
else:
pre.next = cursor
anchor = cursor
cursor = cursor.next
if anchor.next != None:
pre.next = None
return dummyHead.next