2. Add Two Numbers

[hwangnk1004]

2. Add Tow Numbers

https://leetcode.com/problems/add-two-numbers/

[hwangnk1004]

/**
 * 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 result = new ListNode(0);
        ListNode node = result;

        int count = 0;

        while (l1 != null || l2 != null) {
            int sum = count;

            if (l1 != null) {
                sum += l1.val;
                l1 = l1.next;
            }
            if (l2 != null) {
                sum += l2.val;
                l2 = l2.next;
            }

            count = sum / 10;
            sum %= 10;
            result.next = new ListNode(sum);
            result = result.next;

        }

        if (count > 0) {
            result.next = new ListNode(count);
        }

        return node.next;
    }
}

시간 복잡도 = O(n)