<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 {
public:
    bool isValid(int n, int i, int j){
        return i >= 0 && j >= 0 && i < n && j < n;
    }
    void dfs(int i, int j, int n, vector<vector<bool>>& visited, vector<vector<bool>>& v){
        if(!isValid(n,i,j) || visited[i][j] || !v[i][j])return;
        visited[i][j] = true;
        dfs(i+1,j,n,visited,v);
        dfs(i,j+1,n,visited,v);
        dfs(i-1,j,n,visited,v);
        dfs(i,j-1,n,visited,v);
        return;
    }
    int regionsBySlashes(vector<string>& grid) {
        int n = grid[0].size();
        int mn = 3*n;
        cout<<n<<endl;
        vector<vector<bool>> v(mn, vector<bool>(mn, 1));
        for(int i = 0; i < n; i++){
            for(int j = 0; j < n; j++){
                if(grid[i][j] == '/'){
                    int mi = i*3;
                    int mj = j*3;

                    v[mi][mj+2] = false;
                    v[mi+1][mj+1] = false;
                    v[mi+2][mj] = false;
                }
                else if(grid[i][j] == ' ')continue;
                else {
                    int mi = i*3;
                    int mj = j*3;

                    v[mi][mj] = false;
                    v[mi+1][mj+1] = false;
                    v[mi+2][mj+2] = false;
                }
            }
        }


        int comp = 0;
        vector<vector<bool>> visited(mn, vector<bool>(mn, 0));
        for(int i = 0; i < 3*n; i++){
            for(int j = 0; j < 3*n; j++){
                if(visited[i][j] == 0 && v[i][j] == 1){
                    comp++;
                    dfs(i,j,3*n,visited,v);
                }
            }
        }

        return comp;
    }
};
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