Identifying the reorder pattern

The linked list problems that require reordering in place in the list are the only problems that can be solved using the reorder technique. These are generally medium problems where we split the list using some function and then merge them back together using another function. Many such problems also have smaller subproblems that require other techniques like reversal or fast and slow pointers to find the middle. If the problem statement or its solution follows the generic template below, it can be solved by applying the split list technique.

Example

Let's consider the following problem as an example to better understand how to identify and solve a problem using the reorder technique.