- # Definition for singly-linked list.
- # class ListNode:
- # def __init__(self, val=0, next=None):
- # self.val = val
- # self.next = next
- class Solution:
- def addTwoNumbers(self, l1: Optional[ListNode], l2: Optional[ListNode]) -> Optional[ListNode]:
- dummy=ListNode()
- cur=dummy
- carrier=0
- while l1 or l2 or carrier:
- sum=(l1.val if l1 else 0)+(l2.val if l2 else 0)+carrier
- cur.next=ListNode(sum%10)
- carrier=sum//10
- if l1:
- l1=l1.next
- if l2:
- l2=l2.next
- return dummy.next