def swapPairs(self, head: ListNode) -> ListNode:
if head is not None:
pre = head
curr = head
next = curr.next
while curr is not None and curr.next is not None:
# swap node
curr.next = next.next
next.next = curr
if curr == head:
pre = next
head = pre
else:
pre.next = next
pre = pre.next
# move to next node
pre = curr
curr = curr.next
if curr is not None:
next = curr.next
head.print_all()
return head
def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
curr1 = l1
curr2 = l2
carry = 0
total = None
current = None
while curr1 != None or curr2 != None:
sum = 0
sum += carry if carry != 0 else 0
sum += curr1.val if curr1 != None else 0
sum += curr2.val if curr2 != None else 0
if sum >= 10:
sum -= 10
carry = 1
else:
carry = 0
if total == None:
total = ListNode(sum)
current = total
else:
current.next = ListNode(sum)
current = current.next
curr1 = curr1.next if curr1 != None else None
curr2 = curr2.next if curr2 != None else None
if carry > 0:
current.next = ListNode(carry)
return total
def list_node_generator(nums):
if len(nums) == 0:
return None
t = ListNode(nums[0])
head = t
for i in range(1, len(nums)):
t.next = ListNode(nums[i])
t = t.next
return head
def array_to_list_node(data: []):
if data is None or len(data) == 0:
return None
node = ListNode(data[0])
curr = node
for i in range(1, len(data)):
curr.next = ListNode(data[i])
curr = curr.next
return node
def method1(ln):
if ln is None or ln.next is None:
return ln
arr = []
while ln.next:
arr.append(ln.val)
ln = ln.next
arr.append(ln.val)
ll = res = ListNode(0)
for i in arr[::-1]:
res.next = ListNode(i)
res = res.next
return ll.next
def add_two_numbers3(l1, l2):
l3 = ListNode(0)
res = l3
carry = 0
while l1 or l2 or carry:
l3.next = ListNode(0)
if l1:
carry += l1.val
l1 = l1.next
if l2:
carry += l2.val
l2 = l2.next
# 获得商和余数
carry, val = divmod(carry, 10)
l3.next.val = val
l3 = l3.next
return res.next
def method3(l):
if l is None:
return l
i = ListNode(l.val)
j = l.next
while j:
temp = j.next
j.next = i
i = j
j = temp
return i
def merge_two_lists(l1, l2):
t = res = ListNode(0)
while l1 and l2:
if l1.val <= l2.val:
res.next = l1
l1 = l1.next
else:
res.next = l2
l2 = l2.next
res = res.next
res.next = l1 or l2
return t.next
def merge_k_lists2(lists):
res = temp = ListNode(0)
q = PriorityQueue()
for list_node in lists:
if list_node:
q.put((list_node.val, list_node))
while not q.empty():
# PriorityQueue ：每次get取最小的值
temp.next = q.get()[1]
temp = temp.next
if temp.next:
q.put((temp.next.val, temp.next))
return res.next
def reverse_k_group(head, k):
t = head
n = 0
res = temp = ListNode(0)
while t:
n += 1
if n == k:
tt = t.next
t.next = None
temp.next = reversed(head)
while temp.next:
temp = temp.next
temp.next = reverse_k_group(tt, k)
return res.next
else:
t = t.next
if head:
temp.next = head
return res.next
def Merge(self, pHead1, pHead2):
# write code here
res = tmp = ListNode(0)
while pHead1 and pHead2:
if pHead1.val <= pHead2.val:
tmp.next = pHead1
pHead1 = pHead1.next
else:
tmp.next = pHead2
pHead2 = pHead2.next
tmp = tmp.next
while pHead1:
tmp.next = pHead1
pHead1 = pHead1.next
tmp = tmp.next
while pHead2:
tmp.next = pHead2
pHead2 = pHead2.next
tmp = tmp.next
return res.next
def add_two_numbers2(l1, l2):
l3 = ListNode(0)
res = l3
carry = 0
while l1 or l2:
l3.next = ListNode(0)
if l1:
carry += l1.val
l1 = l1.next
if l2:
carry += l2.val
l2 = l2.next
l3.next.val = carry % 10
carry = carry // 10
l3 = l3.next
if carry > 0:
l3.next = ListNode(0)
l3.next.val = carry
return res.next
def insert_at_end(self, data):
new_node = ListNode(data)
curr = self.head
while curr.next is not None:
curr = curr.next
curr.next = new_node
def insert_at_beginning(self, data):
new_node = ListNode(data)
new_node.next = self.head
self.head = new_node
def add_two_numbers1(l1, l2):
l3 = ListNode(0)
res = l3
temp = 0
while l1 and l2:
l3.val = (l1.val + l2.val + temp) % 10
temp = (l1.val + l2.val + temp) // 10
l1 = l1.next
l2 = l2.next
if l1 or l2:
l3.next = ListNode(0)
l3 = l3.next
while l1:
l3.val = (l1.val + temp) % 10
temp = (l1.val + temp) // 10
l1 = l1.next
if l1:
l3.next = ListNode(0)
l3 = l3.next
while l2:
l3.val = (l2.val + temp) % 10
temp = (l2.val + temp) // 10
l2 = l2.next
if l2:
l3.next = ListNode(0)
l3 = l3.next
if temp > 0:
l3.next = ListNode(0)
l3.next.val = temp
return res
sum += carry if carry != 0 else 0
sum += curr1.val if curr1 != None else 0
sum += curr2.val if curr2 != None else 0
if sum >= 10:
sum -= 10
carry = 1
else:
carry = 0
if total == None:
total = ListNode(sum)
current = total
else:
current.next = ListNode(sum)
current = current.next
curr1 = curr1.next if curr1 != None else None
curr2 = curr2.next if curr2 != None else None
if carry > 0:
current.next = ListNode(carry)
return total
l1 = ListNode(1)
l2 = ListNode(9)
l2.next = ListNode(9)
s = Solution()
total = s.addTwoNumbers(l1, l2)
def test_add_two_numbers():
'''
思路：
时间复杂度：O(n)
'''
def add_two_numbers1(l1, l2):
l3 = ListNode(0)
res = l3
temp = 0
while l1 and l2:
l3.val = (l1.val + l2.val + temp) % 10
temp = (l1.val + l2.val + temp) // 10
l1 = l1.next
l2 = l2.next
if l1 or l2:
l3.next = ListNode(0)
l3 = l3.next
while l1:
l3.val = (l1.val + temp) % 10
temp = (l1.val + temp) // 10
l1 = l1.next
if l1:
l3.next = ListNode(0)
l3 = l3.next
while l2:
l3.val = (l2.val + temp) % 10
temp = (l2.val + temp) // 10
l2 = l2.next
if l2:
l3.next = ListNode(0)
l3 = l3.next
if temp > 0:
l3.next = ListNode(0)
l3.next.val = temp
return res
# 方法一优化
def add_two_numbers2(l1, l2):
l3 = ListNode(0)
res = l3
carry = 0
while l1 or l2:
l3.next = ListNode(0)
if l1:
carry += l1.val
l1 = l1.next
if l2:
carry += l2.val
l2 = l2.next
l3.next.val = carry % 10
carry = carry // 10
l3 = l3.next
if carry > 0:
l3.next = ListNode(0)
l3.next.val = carry
return res.next
# 方法2 优化，pythonic
def add_two_numbers3(l1, l2):
l3 = ListNode(0)
res = l3
carry = 0
while l1 or l2 or carry:
l3.next = ListNode(0)
if l1:
carry += l1.val
l1 = l1.next
if l2:
carry += l2.val
l2 = l2.next
# 获得商和余数
carry, val = divmod(carry, 10)
l3.next.val = val
l3 = l3.next
return res.next
print()
t1 = ListNode(0)
t2 = ListNode(0)
test1 = t1
test2 = t2
for i in range(1):
t1.val = i + 1
t1.next = ListNode(2)
t1 = t1.next
for i in range(1):
t2.val = 9
t2.next = ListNode(9)
t2 = t2.next
print(test1)
print(test2)
print(add_two_numbers3(test1, test2))