No2 Add Two Numbers.py

# class Solution(object):
#     def addTwoNumbers(self, l1, l2):
#         """
#         :type l1: ListNode
#         :type l2: ListNode
#         :rtype: ListNode
#         """
#         if not l1 and not l2: return None
#         if not l1: return l2
#         if not l2: return l1
#         order = 0
#         len_l1 = self.count_len(l1)
#         len_l2 = self.count_len(l2)
#         if len_l1 < len_l2:
#             head = l2
#         else:
#             head = l1
#         node = head
#         while l1 and l2:
#             n = l1.val + l2.val + order
#             if n >= 10:
#                 head.val = n - 10
#                 order = 1
#             else:
#                 head.val = n + order
#                 order = 0
#             head = head.next
#             l1 = l1.next
#             l2 = l2.next
#         while l1 or l2:
#             head.val = head.val + order
#             order = 0
#             head = head.next
#         return node
#     def count_len(self, l):
#         count = 0
#         while l:
#             count += 1
#             l = l.next
#         return count
class Solution:
    def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
        dummy = cur = ListNode(0)
        carry = 0
        while l1 or l2 or carry:
            if l1:
                carry += l1.val
                l1 = l1.next
            if l2:
                carry += l2.val
                l2 = l2.next
            cur.next = ListNode(carry % 10)
            cur = cur.next
            carry //= 10
        return dummy.next

class ListNode:
    def __init__(self, x):
        self.val = x
        self.next = None



if __name__ == "__main__":
    solu = Solution()
    l1 = ListNode(1)
    l1.next = ListNode(8)
    l2 = ListNode(0)
    solu.addTwoNumbers(l1, l2)