LeetCode/com/zerroi/leetcode/Three23/AddTwoNumbers.java

package com.zerroi.leetcode.Three23;

public class AddTwoNumbers {
    public static void main(String[] args) {
        ListNode l1 = new ListNode(2, new ListNode(2, new ListNode(3)));
        ListNode l2 = new ListNode(5, new ListNode(6, new ListNode(4)));
        SolutionFirst solutionFirst = new SolutionFirst();
        ListNode listNode = solutionFirst.addTwoNumbers(l1, l2);
    }
}

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 SolutionFirst {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode head = new ListNode(-1);
        ListNode cur = head;
        int carry = 0;
        int a = 0, b = 0;
        int value = 0;
        while (l1 != null || l2 != null) {
            if (l1 == null) {
                a = 0;
            } else {
                a = l1.val;
            }

            if (l2 == null) {
                b = 0;
            } else {
                b = l2.val;
            }
            value = a + b + carry;
            carry = value / 10;
            value = value % 10;
            cur.next = new ListNode(value);
            cur = cur.next;
            if (l1 != null) {
                l1 = l1.next;
            }
            if (l2 != null) {
                l2 = l2.next;
            }

            if (carry != 0) {
                cur.next = new ListNode(1);
            }
        }
        return cur;
     }
}