Styjun

File "/home/shubham/PycharmProjects/LeetCode/AddTwoLinkedList.py", line 5, in class Solution: File "/home/shubham/PycharmProjects/LeetCode/AddTwoLinkedList.py", line 35, in Solution addTwoNumber(l1, l2) TypeError: addTwoNumber() missing 1 required positional argument: 'l2'

class ListNode:
 def __init__(self,x):
 self.val=x
 self.next=None
class Solution:
 def addTwoNumber(self,l1,l2):
 head=l3=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

 l3.val=carry%10
 carry=carry//10

 if l1 or l2 or carry:
 l3.next=ListNode(0)
 l3=l3.next
 print(head)
 return head

 l1 = ListNode(2)
 l1 = ListNode(4)
 l1 = ListNode(3)
 l2 = ListNode(5)
 l2 = ListNode(6)
 l2 = ListNode(4)
 addTwoNumber(l1, l2)

I see a few issues with your code.

First of all, Python is whitespace based language.

As a result, your chunk of code

l1 = ListNode(2)
l1 = ListNode(4)
l1 = ListNode(3)
l2 = ListNode(5)
l2 = ListNode(6)
l2 = ListNode(4)
addTwoNumber(l1, l2)

is actually in the body of your Solution class.

This needs to be pulled out to the global scope of the file. To make this post shorter, I've removed the body of your code.

class Solution:
 # put your code in here

s = Solution()
l1 = ListNode(2)
l2 = ListNode(6)
answer = s.addTwoNumber(l1, l2)

Notice, how I also created an instance of Solution. We need to do this because addTwoNumber is an instance method of Solution

Then you run that file with python your_filename.py

You are getting TypeError: addTwoNumber() missing 1 required positional argument: 'l2' because Python automatically supplies the self variable which references an instance of an object when you invoke an instance method.

However, you have not allowed Python to supply that self because it is currently being called like it is a static method so it fills the arguments left to right. Which means, it is passed "self" and "l1" with l1 and l2 respectively but your function expects 3 arguments.

Function addTwoNumber is a member function, so it needs value of self to be passed either as addTwoNumber(selfValue, l1, l2) or as selfValue.addTwoNumber(l1, l2).

Just replace selfValue whith whatever value you want to pass as self parameter.