Add-2-numbers.cpp

/**

 * Definition for singly-linked list.

 * struct ListNode {

 *     int val;

 *     ListNode *next;

 *     ListNode() : val(0), next(nullptr) {}

 *     ListNode(int x) : val(x), next(nullptr) {}

 *     ListNode(int x, ListNode *next) : val(x), next(next) {}

 * };

 */

class Solution {

public:

    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {

        ListNode *dummy=new ListNode();

        ListNode *temp=dummy;

        int carry=0;

        while(l1!=NULL || l2!=NULL || carry){

            int sum=0;

            if(l1!=NULL){

                sum+=l1->val;

                l1=l1->next;

            }

            

            if(l2!=NULL){

                sum+=l2->val;

                l2=l2->next;

            }

            

            sum+=carry;

            carry=sum/10;

            ListNode *node=new ListNode (sum%10);

            temp->next = node;

            temp=temp->next;

        }

        

        return dummy->next;

        

    }

};