<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<int>> matrix(n*3, vector<int>(n*3, 0));
        for(int i = 0; i < n; i++){
            for(int j = 0; j < n; j++){
                if(grid[i][j] == ' '){
                }
                else if(grid[i][j] == '/'){
                    matrix[i*3][j*3+2] = 1;
                    matrix[i*3+1][j*3+1] = 1;
                    matrix[i*3+2][j*3] = 1;
                }
                else{
                    matrix[i*3][j*3] = 1;
                    matrix[i*3+1][j*3+1] = 1;
                    matrix[i*3+2][j*3+2] = 1;
                }
            }
        }
        int island = 0;
        for(int i = 0; i < n*3; i++)
        {
            for(int j = 0; j < n*3; j++)
            {
                if(matrix[i][j] != 0) continue;
                queue<pair<int,int>> q;
                q.push({i, j});
                while(!q.empty()){
                    auto [x, y] = q.front();
                    q.pop();
                    if(x-1>=0 && matrix[x-1][y]==0){
                        q.push({x-1, y});
                        matrix[x-1][y] = 1;
                    }
                    if(x+1<n*3 && matrix[x+1][y]==0){
                        q.push({x+1, y});
                        matrix[x+1][y] = 1;
                    }
                    if(y-1>=0 && matrix[x][y-1]==0){
                        q.push({x, y-1});
                        matrix[x][y-1] = 1;
                    }
                    if(y+1<n*3 && matrix[x][y+1]==0){
                        q.push({x, y+1});
                        matrix[x][y+1] = 1;
                    }
                }
                island++;
            }
        }
        return island;
    }
};
18496