Add Numbers

AddNumbers.java

class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        
        return addNumbersHelper(l1, l2, 0);
        
    }
    
    public ListNode addNumbersHelper(ListNode l1, ListNode l2, int carry) {
        
        if(l1 == null && l2 == null && carry == 0) {
            
            return null;
        }
        
        int value = carry;
        
        if(l1 != null) {
            
            value += l1.val;
            
        }
        
        if(l2 != null) {
            
            value += l2.val;
            
        }
        
        ListNode result = new ListNode(value%10);
        
        if(l1 != null || l2 != null) {
            
            ListNode more = addNumbersHelper(l1 == null? null: l1.next,l2 == null? null: l2.next, value >= 10? 1:0);
            
            result.next = more;
            
        }
        
        return result;
        
    }
    
}