<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 {
    vector<vector<int>> dir{{-1,0},{1,0},{0,1},{0,-1}};
public:
    void dfs(int i,int j,vector<vector<int>> &grid){
        if (i<0 || i>= grid.size() || j <0 || j >= grid[0].size() || grid[i][j] != 0) return;
        grid[i][j] = 2;
        for(auto &d: dir){
            dfs(i+d[0],j+d[1],grid);
        }
    }
    int regionsBySlashes(vector<string>& grid) {
        vector<vector<int>> grid2(grid.size()*3,vector<int>(grid[0].size()*3,0));

        for(int i=0;i<grid.size();++i){
            for(int j=0;j<grid.size();++j){
                if (grid[i][j] == '/'){
                    int x = 3*i;
                    int y = 3*j;
                    grid2[x+2][y] = 1;
                    grid2[x+1][y+1] = 1;
                    grid2[x][y+2] = 1;
                }
                else if(grid[i][j] == '\\'){
                    int x = 3*i;
                    int y = 3*j;
                    grid2[x][y] = 1;
                    grid2[x+1][y+1] = 1;
                    grid2[x+2][y+2] = 1;
                }
            }
        }

        int regions{0};
        for(int i=0;i<grid2.size();++i){
            for(int j=0;j<grid2[0].size();++j){
                if (grid2[i][j] == 0){
                    dfs(i,j,grid2);
                    ++regions;
                }
            }
        }
        return regions;
    }
};
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