032_Add_Two_Numbers

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.

C++

using namespace std;
class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {

        ListNode* head = new ListNode(0);
        ListNode* curr = head;
        int carry = 0;

        while(l1 != NULL || l2 != NULL || carry!=0){
            int x = 0, y = 0;
            if(l1){
                x = l1->val;
            }
            if(l2){
                 y = l2->val;
            }
            int sum = carry+x+y;
            carry = sum/10;
            curr->next = new ListNode(sum % 10);
            curr = curr->next;
            if(l1){
                l1 = l1->next;
            }
            if(l2){
                l2 = l2->next;
            }
        }
        return head->next;
    }
};