<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:
        m, n = len(grid), len(grid[0])

        def get_neighbors(i, j, part):
            if i<0 or i>=m or j<0 or j>=n:
                return []
                
            if part == 0:
                return [(i, j-1, 2),] + ([(i, j, 3),] if grid[i][j] != '/' else []) + ([(i, j, 1),]  if grid[i][j] != '\\' else [])
            elif part == 1:
                return [(i-1, j, 3)] +  ([(i, j, 0),] if grid[i][j] != '\\' else []) +  ([(i, j, 2),] if grid[i][j] != '/' else [])
            elif part == 2:
                return [(i, j+1, 0)] +  ([(i, j, 3),] if grid[i][j] != '\\' else []) + ([(i, j, 1),] if grid[i][j] != '/' else [])
            else:
                return [(i+1, j, 1)] +  ([(i, j, 2),] if grid[i][j] != '\\' else []) +  ([(i, j, 0),] if grid[i][j] != '/' else [])


        visit = set()
        components = 0
        def dfs(i, j, part):
            if i<0 or i>=m or j<0 or j>=n or (i, j, part) in visit:
                return
            
            visit.add((i, j, part))
            # print(i, j, part, get_neighbors(i, j, part))
            for nei_i, nei_j, nei_part in get_neighbors(i, j, part):
                dfs(nei_i, nei_j, nei_part)

        for i in range(m):
            for j in range(n):
                for part in range(4):
                    if (i, j, part) not in visit:
                        print("visiting", (i, j, part))
                        components += 1
                        dfs(i, j, part)

        return components


            
        
20604