You are given an $m \times n$ matrix maze with $0$ indexed grid positions consisting of empty cells denoted by '.' and walls denoted by '+'. You are also provided an array entrance = $[$entrance_row, entrance_col$]$ indicating the coordinates of the cell where you start.

From any cell, you can move to an adjacent empty cell in one of the four cardinal directions: up, down, left, or right. You cannot enter a cell containing a wall, and you cannot walk outside the boundaries of the grid.

An exit is defined as any empty cell located on the border of maze that is not the entrance itself.

Return the minimum number of steps required to travel from entrance to the closest exit. If no path to an exit exists, return $-1$.

Constraints:

• maze.length $==$ m

• maze[i].length $==$ n

• $1 \leq$ m, n $\leq 100$

• maze[i][j] is either '.' or '+'

• entrance.length $== 2$

• $0 \leq$ entrance_row $<$ m

• $0 \leq$ entrance_col $<$ n

• entrance will always be an empty cell

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.