Add Two Numbers - LeetCode 2

 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.

 

Example 1:

Input: l1 = [2,4,3], l2 = [5,6,4]
Output: [7,0,8]
Explanation: 342 + 465 = 807.

Example 2:

Input: l1 = [0], l2 = [0]
Output: [0]

Example 3:

Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
Output: [8,9,9,9,0,0,0,1]

 

Solution(only function):

/**

 * 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 dh=new ListNode(0);

        ListNode l3=dh;

        

        int carry=0;

        

        while(l1!=null ||  l2!=null)

        {

            int l1_val=l1!= null?l1.val:0;

            int l2_val=l2!= null?l2.val:0;

            

            int currSum=l1_val+l2_val+carry;

            carry=currSum/10;            

            int lastDigit=currSum%10;

            

            ListNode newNode=new ListNode(lastDigit);

            l3.next=newNode;

            

            if(l1!=null) l1=l1.next;

            if(l2!=null) l2=l2.next;

            l3=l3.next;

            

            

        }

       if(carry>0){

           ListNode newNode=new ListNode(carry);

           l3.next=newNode;

           l3=l3.next;

       }

        return dh.next;

        

    }

}