Given a binary string s, return the minimum number of character swaps required to transform s into an alternating string, or $-1$ if it is impossible to do so.

A string is called alternating if no two adjacent characters are equal. In a single swap, you can choose any two characters in s and swap their positions.

Constraints:

• $1 \leq$ s.length $\leq 1000$

• s[i] is either '0' or '1'.

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.