added: add two numbers

Author: mihirs16

14. Questions/leetcode 02 - add two numbers.py

@@ -0,0 +1,38 @@
+# add two numbers | leetcode 02 | https://leetcode.com/problems/add-two-numbers/
+
+# Definition for singly-linked list.
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+class Solution:
+    def addTwoNumbers(self, l1: list[ListNode], l2: list[ListNode]) -> list[ListNode]:
+        res = ListNode()
+        head = res
+
+        while l1 != None or l2 != None:
+            if l1 == None:
+                this_val = res.val + l2.val
+                l2 = l2.next
+            elif l2 == None:
+                this_val = res.val + l1.val
+                l1 = l1.next
+            else:                
+                this_val = res.val + l1.val + l2.val
+                l1, l2 = l1.next, l2.next
+
+            this_digit = this_val % 10
+            next_digit = this_val // 10
+
+            res.val = this_digit
+            if l1 != None or l2 != None:
+                res.next = ListNode(next_digit)
+                res = res.next
+                
+        if next_digit > 0:
+            res.next = ListNode(next_digit)
+            res = res.next
+
+        return head
+