<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<string> visited;
    int regions = 0;
public:
    int regionsBySlashes(vector<string>& grid) {
        int n = grid.size();
        int m = grid[0].size();
        vector<string> newgrid(3*n, string(3*m, ' '));
        for (int i = 0; i < n; i++) for (int j=0; j < m; j++) {
            if (grid[i][j] == '/') {
                newgrid[3*i][3*j+2] = '.';
                newgrid[3*i+1][3*j+1] = '.';
                newgrid[3*i+2][3*j] = '.';
            }
            if (grid[i][j] == '\\') {
                newgrid[3*i][3*j] = '.';
                newgrid[3*i+1][3*j+1] = '.';
                newgrid[3*i+2][3*j+2] = '.';
            }
        }
        for (int i = 0; i < 3*n; i++) for (int j=0; j < 3*m; j++) {
            if (newgrid[i][j] != '.') {
                regions++;
                visit(newgrid, i, j);
            }
        }

        return regions;
    }

    void visit(vector<string>& grid, int i, int j) {
        auto inside = [&](int i, int j) {
            return i >= 0 && i < grid.size() && j>=0 && j<grid[0].size();
        };
        if (!inside(i, j)) return;
        if (grid[i][j] == '.') return;
        grid[i][j] = '.';
        visit(grid, i, j+1);
        visit(grid, i, j-1);
        visit(grid, i+1, j);
        visit(grid, i-1, j);
    }
};
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