<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:
    vector<vector<int>>vis;
    vector<pair<int,int>>moves = {{1,0},{-1,0},{0,1},{0,-1}};
    void dfs(int x, int y, vector<vector<int>>&g){
        vis[x][y] = 1;
        for(auto v : moves){
            int nx = x + v.first;
            int ny = y + v.second;
            if(nx>=0 && nx<g.size() && ny>=0 && ny<g.size() && !vis[nx][ny] && g[nx][ny] == 0){
                dfs(nx,ny,g);
            }
        }
    }
    int regionsBySlashes(vector<string>& grid) {
        int n = grid.size(), connComp = 0;
        vector<vector<int>>g(3*n);
        int row = 0;
        for(int i=0;i<n;i++){
            for(int j=0;j<n;j++){
                if(grid[i][j] == ' '){
                    for(int k=row;k<=row+2;k++){
                        for(int l=1;l<=3;l++){
                            g[k].push_back(0);
                        }
                    }
                }
                else if(grid[i][j] == '/'){
                    for(int k=row;k<=row+2;k++){
                        if(k==row){
                            g[k].push_back(0);
                            g[k].push_back(0);
                            g[k].push_back(1);
                        }
                        else if(k == row+1){
                            g[k].push_back(0);
                            g[k].push_back(1);
                            g[k].push_back(0); 
                        }
                        else{
                            g[k].push_back(1);
                            g[k].push_back(0);
                            g[k].push_back(0);  
                        }
                    }
                }
                else{
                    for(int k=row;k<=row+2;k++){
                        if(k==row){
                            g[k].push_back(1);
                            g[k].push_back(0);
                            g[k].push_back(0);
                        }
                        else if(k == row+1){
                            g[k].push_back(0);
                            g[k].push_back(1);
                            g[k].push_back(0); 
                        }
                        else{
                            g[k].push_back(0);
                            g[k].push_back(0);
                            g[k].push_back(1);  
                        }
                    }
                }
            }
            row+=3;
        }
        vis.assign(3*n,vector<int>(3*n,0));
        for(int i=0;i<3*n;i++){
            for(int j=0;j<3*n;j++){
                if(g[i][j] == 0 && vis[i][j] == 0){
                    connComp++;
                    dfs(i,j,g);
                }
            }
        }
        return connComp;
    }
};
18801