Add Two Numbers Represented as Linked List

In this tutorial, we explore how to add two numbers represented as linked lists. The task involves summing two linked lists where each node contains a digit of the number. We discuss different approaches, including the naive approach, which creates a new linked list to store the sum, using an iterative method to traverse the two lists and reverse the nodes as needed. We also cover methods like storing the sum directly in the longer list and using recursion for a more efficient solution. The explanation ensures that leading zeros are handled appropriately in the input and output lists.

We go over the time complexity of these solutions, with the naive approach being O(m + n), where m and n are the sizes of the two linked lists. More optimized approaches, such as storing sums in the longer list and recursion, achieve O(m + n) time complexity but reduce auxiliary space usage. Each method is explained in detail, along with the handling of carries and the final result.

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