Naive Python Solution

  • 3
    class Solution(object):
        def addTwoNumbers(self, l1, l2):
            c1, c2 = '', ''
            while l1:
                c1 += str(l1.val)
                l1 =
            while l2:
                c2 += str(l2.val)
                l2 =
            num = str(int(c1) + int(c2))
            dummy = ListNode(0)
            c = dummy
            for i in range(len(num)):
       = ListNode(num[i])
                c =

  • 0

    Maybe you shouldn't even consider this as a naive solution, because the spirit of this exercise is to show how large numbers are added when there is a bit limit (I think), therefore int(str(huge_number)) already fails the purpose

  • 0

    @lucidsushi How did you know the "sprit of this excise"?

  • -1

    @lilixu Someone told me about it when I shared them the original question (this one is part2). But you can imagine if a language had a method called add_two_linkedlist. Is there really a point to show the solution is return add_two_linkedlist(l1, l2)? You can check out the editoral comments for what the spirit of the question is

  • -1

    @lilixu I agree with lucidsushi's opinion. According to the level of difficulty of this question, a medium level, one of test points should be how to manipulate singly linked lists to achieve the goal of summation of two lists; the other one point to check is how to use dfs idea to design your algorithm for this question. Your algorithm design is pretty easy, because all built-in Python functions you use in your code hide the test points. If you are preparing for technical interview, you should try not to use built-in Python functions in your solution. For easy level questions, you could use them.

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