两数相加

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

class :
    def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
        result = ListNode(0)
        r = result
        carry = 0
        while(l1 or l2 or carry!=0):
            a = l1.val if l1 else 0
            b = l2.val if l2 else 0
            aplusb = (a + b + carry)%10
            carry = (a+b + carry )//10
            r.next = ListNode(aplusb)
            r = r.next
            print(aplusb)
            l1 = l1.next if l1 else None
            l2 = l2.next if l2 else None
            if(l1 or l2 or carry):
                print(" -> ")
        result = result.next
        return result;