package com.eip.chapter8;

  /*
    Problem: How to add 2 list based integers where the least significant digits come first
    Solution: - Follow normal grade school based addition
     */
public class AddListBasedIntegers {
    public ListNode<Integer> addTwoNumbers(ListNode<Integer> L1, ListNode<Integer> L2) {
        ListNode<Integer> dummyHead = new ListNode<Integer>(0,null);
        ListNode<Integer> placeIter = dummyHead;

        int carry = 0 ;
        while (L1 != null || L2 != null){
            int sum = carry;
            if(L1 != null){
                sum = sum + L1.data;
                L1 = L1.next;
            }
            if(L2 != null){
                sum = sum + L2.data;
                L2 = L2.next;
            }
            carry = sum /10;
            sum = sum %10;
            placeIter.next = new ListNode<Integer>(sum, null);
            placeIter = placeIter.next;
        }

        if(carry > 0){
            placeIter.next = new ListNode<Integer>(carry,null);
        }
        return dummyHead.next;
    }


}