# Add Two Numbers Linked List Python – LeetCode Solutions

LeetCode has a coding Problem in Its’ Algorithm Section which is Add Two Numbers Linked List Python. Today We are going to solve this problem. LeetCode Link of the Problem is HERE.

#### Question

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. Add the two numbers and return the sum as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Input: l1 = [2,4,3], l2 = [5,6,4] Output: [7,0,8] Explanation: 342 + 465 = 807.

#### Conditions

• The number of nodes in each linked list is in the range [1, 100].
• No leading Zeros in Linked List
• 0 <= Node.val <= 9

#### Solution toAdd Two Numbers Linked List Python

The Skeleton Code Given By LeetCode is:

``````# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution(object):
def addTwoNumbers(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""``````

Firstly I created two Variables to store the two input linked Lists as a string. To do so I Looped through the linked list and store the variables as a string. Reversed the String for Addition.

``````# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution(object):
def addTwoNumbers(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""
a1 = ""
a2 = ""
while l1.next != None:
a1 += str(l1.val)
l1 = l1.next
while l2.next != None:
a2 += str(l2.val)
l2 = l2.next
a1 += str(l1.val)
a2 += str(l2.val)
a1 = a1[::-1]
a2 = a2[::-1]``````

Added the Two Variables as Integers. Created a New Linked List Node and Stored the Integers as Nodes of Linked List.

``````# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution(object):
def addTwoNumbers(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""
a1 = ""
a2 = ""
while l1.next != None:
a1 += str(l1.val)
l1 = l1.next
while l2.next != None:
a2 += str(l2.val)
l2 = l2.next
a1 += str(l1.val)
a2 += str(l2.val)
a1 = a1[::-1]
a2 = a2[::-1]
a3 = int(a1) + int(a2)
a3 = list(str(a3))
x = ListNode()
for i in range(0,len(a3)):
if i == len(a3)-1:
x.val = a3[i]
else:
temp = ListNode()
temp.val = a3[i]
temp.next = x.next
x.next = temp
return x``````

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