# LeetCode 2. Add Two Numbers

## 양수(Positive Number)들로 이루어진 2개의 리스트를 각 인덱스 별로 더한 결과 구하기

#Algotithm #LeetCode

# Description

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.

Example

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

/**
* public class ListNode {
*     int val;
*     ListNode next;
*     ListNode(int x) { val = x; }
* }
*/
class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {

}
}


# Solution

/**
* public class ListNode {
*     int val;
*     ListNode next;
*     ListNode(int x) { val = x; }
* }
*/

/**
*
* @author kimtaeng
* created on 2018. 1. 9.
*/
public class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode operand1 = l1;
ListNode operand2 = l2;
ListNode resultNode = new ListNode(0);
ListNode currentNode = resultNode;

int sum = 0;

while (operand1 != null || operand2 != null) {
sum = sum / 10;
if(operand1 != null) {
sum = sum + operand1.val;
operand1 = operand1.next;
}

if(operand2 != null) {
sum = sum + operand2.val;
operand2 = operand2.next;
}

currentNode.next = new ListNode(sum % 10);
currentNode = currentNode.next;
}

if(sum / 10 == 1) {
currentNode.next = new ListNode(1);
}

return resultNode.next;
}
}