You are given a binary string s consisting only of the characters '0' and '1'.

You may choose to swap any two characters in s at most once.

A substring of s is called balanced if the count of '0' characters is equal to the count of '1' characters within that substring.

Return the maximum possible length of a balanced substring that can be formed after at most one swap.

Constraints:

• $1 \leq$ s.length $\leq 10^5$

• s consists only of the characters '0' and '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.