LeetCode 2. Add Two Numbers

Post by ailswan Nov. 25, 2025

2. Add Two Numbers

Problem Statement

link: LeetCode.cn 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:

Input: l1 = [2,4,3], l2 = [5,6,4] Output: [7,0,8]

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

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 Approach

Algorithm

Complexity

time complexity: space complexity:

Implement

    class Solution:
    def