<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:
    int regionsBySlashes(vector<string>& grid) {
        int n = grid.size();
        vector<vector<char>> g(n * 3, vector<char>(n * 3, '1'));

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                cout << grid[i][j] << " ";
                if (grid[i][j] == ' ') {
                    continue;
                } else if (grid[i][j] == '/') {
                    g[i * 3][j * 3 + 2] = '0';
                    g[i * 3 + 1][j * 3 + 1] = '0';
                    g[i * 3 + 2][j * 3] = '0';
                } else {
                    g[i * 3][j * 3] = '0';
                    g[i * 3 + 1][j * 3 + 1] = '0';
                    g[i * 3 + 2][j * 3 + 2] = '0';
                }
            }
        }

        return numIslands(g);
    }

    int numIslands(vector<vector<char>>& grid) {
        int n = grid.size();
        int m = grid[0].size();
        int cnt = 0;

        vector<vector<bool>> visited(n, vector<bool>(m));

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (grid[i][j] == '1' && !visited[i][j]) {
                    dfs(grid, visited, i, j);
                    cnt++;
                }
            }
        }

        return cnt;
    }

    void dfs(vector<vector<char>>& grid, 
            vector<vector<bool>>& visited, 
            int i, 
            int j) {
        if (i < 0 || i >= grid.size() || j < 0 || j >= grid[0].size() || 
        grid[i][j] == '0' || visited[i][j]) {
            return;
        }

        visited[i][j] = 1;
        dfs(grid, visited, i + 1, j);
        dfs(grid, visited, i - 1, j);
        dfs(grid, visited, i, j + 1);
        dfs(grid, visited, i, j - 1);
    }
};
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