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 contain a single digit. Add the two numbers and return it as a linked list.
You may assume the two numbers do not contain any leading zero, except the number 0 itself.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.
# Definition for singly-linked list. class ListNode: def __init__(self, x): self.val = x self.next = None class Solution: def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode: head, curr = 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 curr.next = ListNode(carry % 10) curr = curr.next carry //= 10 return head.next
Runtime: 88 ms, faster than 16.90% of Python3 online submissions for Add Two Numbers.
Memory Usage: 14 MB, less than 5.67% of Python3 online submissions for Add Two Numbers.