Grokking Data Structures & Algorithms for Coding Interviews

Solution: Merge Two Sorted Lists 

## Problem Statement

Given the head of two sorted linked lists, `l1` and `l2`. 

Return a new sorted list created by merging together the nodes of the first two lists.

## Examples

1. **Example 1:**
   - **Input:**
     ```
     [1, 3, 5]
     [2, 4, 6]
     ```
   - **Expected Output:**
     ```
     [1, 2, 3, 4, 5, 6]
     ```
   - **Justification:** Merging the two sorted linked lists, node by node, results in a single sorted linked list containing all elements from both input lists.

2. **Example 2:**
   - **Input:**
     ```
     [2, 4, 6]
     [1, 3, 5]
     ```