def add_two_number(self, l1: ListNode, l2: ListNode) -> ListNode:
'''
两个链表相加
Args:
l1: 链表l1
l2: 链表l2
Returns:
链表的和
'''
node = ListNode(-1)
head = node
carry = 0
while not l1 or not l2:
num1 = 0 if not l1 else l1.val
num2 = 0 if not l2 else l2.val
total = num1 + num2 + carry
node.next = ListNode(total % 10)
node = node.next
carry = total // 10
if not l1:
l1 = l1.next
if not l2:
l2 = l2.next
if carry > 0:
node.next = ListNode(carry)
return head.next
def test_first_list_bigger():
l1 = ListNode(5)
l1.next = ListNode(10)
l1.next.next = ListNode(200)
l2 = ListNode(100)
l2.next = ListNode(150)
l3 = merge(l1, l2)
assert list_is_sorted(l3)
def test_simple_example():
l1 = ListNode(1)
l1.next = ListNode(2)
l1.next.next = ListNode(4)
l2 = ListNode(1)
l2.next = ListNode(3)
l2.next.next = ListNode(4)
l3 = merge(l1, l2)
assert list_is_sorted(l3)
def create_rand_sorted_list(n: int) -> ListNode:
node = ListNode(random.randint(0, 10))
head = node
for i in range(n - 1):
node.next = ListNode(random.randint(node.value, node.value + 10))
node = node.next
return head
def test_multiple_elements():
l1 = ListNode(2)
l1.next = ListNode(5)
l1.next.next = ListNode(10000)
assert list_is_sorted(l1)
l1.next.next.next = ListNode(6)
assert not list_is_sorted(l1)
def merge_two_lists_2(self, l1: ListNode, l2: ListNode) -> ListNode:
'''
合并两个链表
Args:
l1: l1链表
l2: l2链表
Returns:
合并后的链表
'''
if not l1:
return l2
if not l2:
return l1
if l1.val <= l2.val:
l1.next = self.merge_two_lists_2(l1.next, l2)
return l1
else:
l2.next = self.merge_two_lists_2(l1, l2.next)
return l2
def merge_two_lists(self, l1: ListNode, l2: ListNode) -> ListNode:
'''
合并两个链表
Args:
l1: l1链表
l2: l2链表
Returns:
合并后的链表
'''
node = ListNode(-1)
head = node
while l1 and l2:
if l1.val <= l2.val:
node.next = l1
l1 = l1.next
else:
node.next = l2
l2 = l2.next
node = node.next
if not l1:
node.next = l2
if not l2:
node.next = l1
return head.next
def detect_cycle_2(self, head: ListNode) -> ListNode:
'''
头结点
Args:
head: 头结点位置
Returns:
环中头结点位置
'''
if not head or not head.next:
return None
node = ListNode(-1)
node.next = head
cur = node
list_node_set = set()
while cur.next:
if cur.next in list_node_set:
return cur.next
cur = cur.next
list_node_set.add(cur)
return None
def remove_nth_from_end(self, head: ListNode, n: int) -> ListNode:
'''
删除倒数第n个点
Args:
head: 头节点
n: 倒数n个数
Returns:
删除后的结果
'''
if head == None or head.next == None:
return None
dummy = ListNode(-1)
dummy.next = head
node1 = dummy
node2 = dummy
for i in range(n):
node2 = node2.next
while node2.next:
node1 = node1.next
node2 = node2.next
node1.next = node1.next.next
return dummy.next
Args:
head: 头结点
Returns:
中间结点
'''
if not head or not head.next:
return head
count = 0
temp = head
while temp:
count += 1
temp = temp.next
for i in range(count // 2):
head = head.next
return head
if __name__ == '__main__':
node1 = ListNode(1)
node2 = ListNode(2)
node3 = ListNode(3)
node4 = ListNode(4)
node5 = ListNode(5)
node1.next = node2
node2.next = node3
node3.next = node4
node4.next = node5
solution = Solution()
node = solution.middle_linked_list(node1)
assert node.val == 3