Add Two Numbers
Problem
You are given two non-empty linked lists, l1 and l2, where each represents a non-negative integer.
The digits are stored in reverse order, e.g. the number 321 is represented as 1 -> 2 -> 3 -> in the linked list.
Each of the nodes contains a single digit. You may assume the two numbers do not contain any leading zero, except the number 0 itself.
Return the sum of the two numbers as a linked list.
Examples
Example 1:
Input: l1 = [1,2,3], l2 = [4,5,6]
Output: [5,7,9]
Explanation: 321 + 654 = 975.
Example 2:
Input: l1 = [9], l2 = [9]
Output: [8,1]
Constraints
1 <= l1.length, l2.length <= 100.0 <= Node.val <= 9
You should aim for a solution with O(m + n) time and O(1) space, where m is the length of list l1 and n is the length of list l2.
Solution
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