Add Two Numbers II
You are given two non-empty linked lists representing two non-negative integers. The most significant digit comes first and each of their nodes contains a single digit. For example, 123 is represented as 1 -> 2-> 3. 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 = [1,2,3], l2 = [4,5,6]
Output: [5,7,9]Explanation: 123 + 456 = 579
Example 2:
Input: l1 = [9,9], l2 = [8,9,7]
Output: [9,9,6]Explanation: 99 + 897 = 996
Constraints:
1 <= l1.length, l2.length <= 1000 <= Node.val <= 9- It is guaranteed that the list represents a number that does not have leading zeros.
Follow up: Could you solve it without reversing the input lists?