Add Two Numbers

medium· Linked Listruns: 0

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each node 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.

wpm 0acc 100%time 0:000 / 543

class Solution:
    def addTwoNumbers(
        self, l1: ListNode | None, l2: ListNode | None
    ) -> ListNode | None:
        dummy = ListNode()
        tail = dummy
        carry = 0
        while l1 or l2 or carry:
            v1 = l1.val if l1 else 0
            v2 = l2.val if l2 else 0
            total = v1 + v2 + carry
            carry = total // 10
            tail.next = ListNode(total % 10)
            tail = tail.next
            l1 = l1.next if l1 else None
            l2 = l2.next if l2 else None
        return dummy.next

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