You are given a $0$ indexed $2$D binary string array bank representing the floor plan of a bank, where $'0'$ represents an empty cell and $'1'$ represents a cell containing a security device.

A laser beam connects two security devices if and only if both conditions are satisfied:

1. The two devices are located on two distinct rows, $r_1$ and $r_2$, where $r_1 < r_2$.

2. For every row $i$ strictly between $r_1$ and $r_2$ ($r_1 < i < r_2$), there are no security devices.

Laser beams function independently, meaning beams do not block or interfere with one another.

Return the total number of laser beams in the bank.

Constraints:

• m $==$ bank.length

• n $==$ bank[i].length

• $1 \leq$ m, n $\leq 500$

• bank[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.