You are given a binary string s and an integer k.

A binary string satisfies the $k$ constraint if at least one of the following conditions holds:

• The total count of '0' characters is at most k.

• The total count of '1' characters is at most k.

Return the total number of substrings of s that satisfy the $k$ constraint.

Constraints:

• $1 \leq$ s.length $\leq 50$

• $1 \leq$ k $\leq$ s.length

• 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.