You are given an array of $2 ext{D}$ integers lists, where each inner array lists[i] is sorted in non decreasing order.

In one operation, you can choose any two lists $a$ and $b$, and merge them into a single sorted list. The cost of this operation is defined as:

Now, let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.