2. Add Two Numbers

/**
 * 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) {
      int carry=0;
      ListNode dum=new ListNode();
      ListNode temp=dum;
      while(l1!=null&&l2!=null){
           int value=(l1.val+l2.val+carry)%10;
            carry=(l1.val+l2.val+carry)/10;
           ListNode node=new ListNode(value);
           temp.next=node;
           l1=l1.next;
           l2=l2.next;
           temp=temp.next;

      }
      while(l1!=null){
        int value=(l1.val+carry)%10;
         carry=(l1.val+carry)/10;
           ListNode node=new ListNode(value);
           temp.next=node;
           l1=l1.next;
          
           temp=temp.next;
      }
       while(l2!=null){
        int value=(l2.val+carry)%10;
         carry=(l2.val+carry)/10;
           ListNode node=new ListNode(value);
           temp.next=node;
           l2=l2.next;
          
           temp=temp.next;
      }
      if(carry!=0){
        ListNode node=new ListNode(carry);
        temp.next=node;
      }
      return dum.next;
    }
   
}