AddTwoNumbers.cpp

#include <iostream>



// 2. Leetcode add two numbers


 // 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* head = new ListNode();
        ListNode* current = head;
        int carry = 0;

        while (l1 != nullptr || l2 != nullptr || carry != 0) {
            int sum = carry;
            if (l1 != nullptr) {
                sum += l1->val;
                l1 = l1->next;
            }
            if (l2 != nullptr) {
                sum += l2->val;
                l2 = l2->next;
            }
            current->next = new ListNode(sum % 10);
            carry = sum / 10;
            current = current->next;
        }

        return head->next;
    }
};

int main()
{
    Solution solution;

    ListNode* l1 = new ListNode(2);
    l1->next = new ListNode(4);
    l1->next->next = new ListNode(3);

    ListNode* l2 = new ListNode(5);
    l2->next = new ListNode(6);
    l2->next->next = new ListNode(4);

    ListNode* result = solution.addTwoNumbers(l1, l2);

    while (result != nullptr) {
        std::cout << result->val << " ";
        result = result->next;
    }


    return 0;
}