Add Two Number

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 contain a single digit. Add the two numbers and return it as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4) Output: 7 -> 0 -> 8

/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) { int lsum = 0, rsum = 0; ListNode* root = new ListNode(0), *p = root, *cur = NULL; int carry = 0; while (l1 || l2 || carry) { int sum = (l1 ? l1->val : 0) + (l2 ? l2->val : 0) + carry; p->next = new ListNode(sum % 10); p = p->next; carry = sum / 10; l1 = l1 ? l1->next : NULL; l2 = l2 ? l2->next : NULL; } return root->next; } };