Given an $m imes n$ binary matrix mat, return the total number of submatrices that contain only $1$s.

Constraints:

• $1 \leq m, n \leq 150$

• m == mat.length

• n == mat[i].length

• mat[i][j] 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.