This problem involves adding two numbers represented by linked lists.
You can find the original problem described on LeetCode.
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.
I could think of three possible approaches one could use to solve this issue.
You can find a complete walkthrough of my solutions on my post.
Below is a table with a summary of the solutions.
| Solutions | Time | Space |
|---|---|---|
| Iterative | O(max(m,n)) |
O(1) |
| Recursive1 | O(max(m,n)) |
O(1) |
| Recursive2 | O(min(m,n)) |
O(1) |