Given a binary string s, return the number of ways to split s into $3$ nonempty substrings such that each substring contains the same number of $'1'$ characters.

Since the answer may be very large, return it modulo $10^9 + 7$.

Constraints:

• $3 \leq$ s.length $\leq 10^5$

• 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.