"""
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):
def addTwoNumbers(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""
if not l1 and not l2:
return [];
temp = ListNode(0);
res = temp;
# use res to store the head pointer of result's linked list.
# The result starts from res.next
flag = 0;
while(l1 or l2):
a = 0;
b = 0;
if l1:
a = l1.val;
l1 = l1.next;
if l2:
b = l2.val;
l2 = l2.next;
s = a + b + flag;
flag = s / 10;
temp.next = ListNode(s%10);
temp = temp.next;
if flag == 1:
temp.next = ListNode(1);
return res.next;
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
public class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode res = new ListNode(-1);
ListNode temp = res;
int carry = 0;
while (l1 != null || l2 != null) {
if (l1 != null) {
carry += l1.val;
l1 = l1.next;
}
if (l2 != null) {
carry += l2.val;
l2 = l2.next;
}
temp.next = new ListNode(carry % 10);
temp = temp.next;
carry /= 10;
}
if (carry > 0) temp.next = new ListNode(carry);
return res.next;
}
}