# 2. Add Two Numbers 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:** ![img](https://raw.githubusercontent.com/Albert-Hu/leetcode/master/solutions/1-50/2/addtwonumber1.jpg) ``` 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. --- # Solution Add two nodes with carrying, store the result into a new node, and make sure that carry passes to the next calculation. These things should notice: - The carrying from the summation from two nodes needs to pass to the next calculation. - The different length between two nodes. See the full [solution](https://github.com/Albert-Hu/leetcode/tree/master/solutions/1-50/2). ###### tags: `leetcode` `Medium` `Linked List` `Math`