<p>An <code>n x n</code> grid is composed of <code>1 x 1</code> squares where each <code>1 x 1</code> square consists of a <code>&#39;/&#39;</code>, <code>&#39;\&#39;</code>, or blank space <code>&#39; &#39;</code>. These characters divide the square into contiguous regions.</p>

<p>Given the grid <code>grid</code> represented as a string array, return <em>the number of regions</em>.</p>

<p>Note that backslash characters are escaped, so a <code>&#39;\&#39;</code> is represented as <code>&#39;\\&#39;</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2018/12/15/1.png" style="width: 200px; height: 200px;" />
<pre>
<strong>Input:</strong> grid = [&quot; /&quot;,&quot;/ &quot;]
<strong>Output:</strong> 2
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2018/12/15/2.png" style="width: 200px; height: 198px;" />
<pre>
<strong>Input:</strong> grid = [&quot; /&quot;,&quot;  &quot;]
<strong>Output:</strong> 1
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2018/12/15/4.png" style="width: 200px; height: 200px;" />
<pre>
<strong>Input:</strong> grid = [&quot;/\\&quot;,&quot;\\/&quot;]
<strong>Output:</strong> 5
<strong>Explanation: </strong>Recall that because \ characters are escaped, &quot;\\/&quot; refers to \/, and &quot;/\\&quot; refers to /\.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>n == grid.length == grid[i].length</code></li>
	<li><code>1 &lt;= n &lt;= 30</code></li>
	<li><code>grid[i][j]</code> is either <code>&#39;/&#39;</code>, <code>&#39;\&#39;</code>, or <code>&#39; &#39;</code>.</li>
</ul>

class Solution:
    def regionsBySlashes(self, grid: List[str]) -> int:
        def splitregion(grid):
            grid_size = len(grid)
            expanded_grid = [[0] * (grid_size * 3) for _ in range(grid_size * 3)]

            for i in range(grid_size):
                for j in range(grid_size):
                    base_row = i * 3
                    base_col = j * 3

                    if grid[i][j] == "\\":
                        expanded_grid[base_row][base_col] = 1
                        expanded_grid[base_row + 1][base_col + 1] = 1
                        expanded_grid[base_row + 2][base_col + 2] = 1
                    
                    elif grid[i][j] == "/":
                        expanded_grid[base_row][base_col + 2] = 1
                        expanded_grid[base_row + 1][base_col + 1] = 1
                        expanded_grid[base_row + 2][base_col] = 1

            return expanded_grid
        

        expanded_grid = splitregion(grid)
        row = len(expanded_grid)
        col = len(expanded_grid[0])

        total = 0

        def dfs(i, j):
            if i < 0 or j < 0 or i >= row or j >= col or expanded_grid[i][j] == 1:
                return
            
            expanded_grid[i][j] = 1
            dfs(i - 1, j)
            dfs(i, j - 1)
            dfs(i + 1, j)
            dfs(i, j + 1)
            return

        for i in range(row):
            for j in range(col):
                if expanded_grid[i][j] == 0:
                    total += 1
                    dfs(i, j)
        
        return total

17668