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
# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution(object):
# maybe standard version
def _addTwoNumbers(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""
p = dummy = ListNode(-1)
carry = 0
while l1 and l2:
p.next = ListNode(l1.val + l2.val + carry)
carry = p.next.val / 10
p.next.val %= 10
p = p.next
l1 = l1.next
l2 = l2.next
res = l1 or l2
while res:
p.next = ListNode(res.val + carry)
carry = p.next.val / 10
p.next.val %= 10
p = p.next
res = res.next
if carry:
p.next = ListNode(1)
return dummy.next
# shorter version
def addTwoNumbers(self, l1, l2):
p = dummy = ListNode(-1)
carry = 0
while l1 or l2 or carry:
val = (l1 and l1.val or 0) + (l2 and l2.val or 0) + carry
carry = val / 10
p.next = ListNode(val % 10)
l1 = l1 and l1.next
l2 = l2 and l2.next
p = p.next
return dummy.next
