def addTwoNumbers(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""
extra = 0
dummy = ListNode(0)
head = dummy
while l1 or l2:
if l1:
n1 = l1.val
else:
n1 = 0
if l2:
n2 = l2.val
else:
n2 = 0
res = (n1 + n2 + extra) % 10
extra = (n1 + n2 + extra) // 10
dummy.next = ListNode(res)
if l1:
l1 = l1.next
if l2:
l2 = l2.next
dummy = dummy.next
if extra != 0:
dummy.next = ListNode(extra)
return head.next
def removeZeroSumSublists(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
if head is None:
return None
dummy = ListNode(0)
dummy.next = head
diff = {}
sum = 0
node = dummy
while node:
sum += node.val
diff[sum] = node
node = node.next
sum = 0
node = dummy
while node:
sum += node.val
node.next = diff[sum].next
node = node.next
return dummy.next
def plusOne(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
if head is None:
return None
dummy = ListNode(0)
dummy.next = head
nine = dummy
while head:
if head.val != 9:
nine = head
head = head.next
node = nine.next
while node:
node.val = 0
node = node.next
nine.val += 1
return dummy if dummy.val == 1 else dummy.next
def addTwoNumbers(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""
if l1 is None:
return l2
if l2 is None:
return l1
stack1 = []
stack2 = []
while l1 or l2:
if l1:
stack1.append(l1.val)
l1 = l1.next
if l2:
stack2.append(l2.val)
l2 = l2.next
dummy = ListNode(0)
extra = 0
while stack1 or stack2:
n1 = stack1.pop() if stack1 else 0
n2 = stack2.pop() if stack2 else 0
sum = n1 + n2 + extra
node = ListNode(sum % 10)
extra = sum // 10
node.next = dummy.next
dummy.next = node
if extra != 0:
node = ListNode(extra)
node.next = dummy.next
dummy.next = node
return dummy.next
def reverseKGroup(self, head, k):
"""
:type head: ListNode
:type k: int
:rtype: ListNode
"""
stack = []
dummy = ListNode(0)
new_head = dummy
node = head
while node:
stack.append(node)
node = node.next
if len(stack) == k:
for i in range(k):
poped = stack.pop()
poped.next = None
dummy.next = poped
dummy = dummy.next
if len(stack) != 0:
dummy.next = stack.pop(0)
return new_head.next
def sortList(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
node = head
length = 0
while node:
node = node.next
length += 1
if length == 0: return
dummy = ListNode(0)
dummy.next = head
interval = 1
while interval < length:
prev = dummy
cur = prev.next
while cur:
first = cur
for j in range(interval - 1):
if cur:
cur = cur.next
if cur is None:
break
second = cur.next
cur.next = None
cur = second
for j in range(interval - 1):
if cur:
cur = cur.next
rest = None
if cur:
rest = cur.next
cur.next = None
cur = rest
prev.next = self.merge(first, second)
while prev.next:
prev = prev.next
prev.next = rest
interval *= 2
return dummy.next
def deleteDuplicates(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
if head is None or head.next is None:
return head
dummy = ListNode(0)
dummy.next = head
prev, cur = dummy, head
while cur:
if cur.next and cur.val == cur.next.val:
cur = self.findSame(prev, cur.val)
else:
cur = cur.next
prev = prev.next
return dummy.next
def reverseBetween(self, head, m, n):
"""
:type head: ListNode
:type m: int
:type n: int
:rtype: ListNode
"""
if head is None or m == n:
return head
dummy = ListNode(0)
dummy.next = head
node = dummy
count = 0
while node and count != m - 1:
node = node.next
count += 1
print(node.val)
self.reverse(node, n - m)
return dummy.next
def swapPairs(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
if head is None or head.next is None:
return head
dummy = ListNode(0)
dummy.next = head
prev = dummy
count = 0
node = prev.next
while node:
count += 1
if count % 2 == 0:
prev = self.swap(prev, node)
node = prev.next
else:
node = node.next
show_linkedlist(dummy.next)
def removeNthFromEnd(self, head, n):
"""
:type head: ListNode
:type n: int
:rtype: ListNode
"""
if head is None:
return None
if head.next is None and n == 1:
return None
count = 0
dummy = ListNode(0)
dummy.next = head
node, cur = dummy, dummy
while node:
if count > n:
cur = cur.next
node = node.next
count += 1
cur.next = cur.next.next
return dummy.next