## Question

You are given two linked lists representing two non-negative numbers. 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.

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


## Solution

Result: Accepted Time: 20ms

class Solution {
public:
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
int carry = 0;
while(l1 || l2 )
{
if(l1)
carry += l1 -> val, l1 = l1->next;
if(l2)
carry += l2 -> val, l2 = l2->next;
tail->next =  new ListNode(carry%10);
tail = tail->next;
carry /= 10;
}
if(carry)
tail->next = new ListNode(carry);

• Time Complexity: $O(max(m,n))$
• Space Complexity: $O(max(m,n))$