Add Two Num

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.

• Example 1:

Input: l1 = [2,4,3], l2 = [5,6,4] Output: [7,0,8] Explanation: 342 + 465 = 807.

• Example 2:

Input: l1 = [0], l2 = [0] Output: [0]

• Example 3:

Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9] Output: [8,9,9,9,0,0,0,1]

Constraints:

• The number of nodes in each linked list is in the range [1, 100].
• 0 <= Node.val <= 9
• It is guaranteed that the list represents a number that does not have leading zeros.

/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} l1
 * @param {ListNode} l2
 * @return {ListNode}
 */
var addTwoNumbers = function(l1, l2) {
  let curry = 0;
  let c1 = l1;
  let c2 = l2;
  const head = {
    pendding: null,
  };
  let c;
  while (c1 || c2 || curry) {
    let sum = (c1?.val || 0) + (c2?.val || 0) + curry;
    debugger
    if (sum >= 10) {
      sum = sum - 10;
      curry = 1;
    } else {
      curry = 0;
    }
    if (!c) {
      head.pendding = c  = {
        val: sum,
        next: null,
      };
    } else {
      c = c.next = {
        val: sum,
        next: null,
      };
    }
    c1 = c1?.next;
    c2 = c2?.next;
  }
  return head.pendding;
};