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 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.
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode() {}
* ListNode(int val) { this.val = val; }
* ListNode(int val, ListNode next) { this.val = val; this.next = next; }
* }
*/
class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode res = new ListNode(0);
ListNode p = res;
int carry = 0;
while (l1 != null || l2 != null || carry != 0) {
int l1val = l1 != null ? l1.val : 0;
int l2val = l2 != null ? l2.val : 0;
int sum = carry + l1val + l2val;
int val = sum % 10;
carry = sum / 10;
ListNode next = new ListNode(val);
p.next = next;
p = next;
if (l1 != null) {
l1 = l1.next;
}
if (l2 != null) {
l2 = l2.next;
}
}
return res.next;
}
}
