<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 dx[4] = {-1, 1, 0, 0};
    int dy[4] = {0, 0, -1, 1};

    bool isValid(int x, int y, int n, int m){
        return !(x < 0 || x >= n || y < 0 || y >= m);
    }

    void dfs(int x, int y, vector<vector<int>> &vis, map<int, vector<int>>& grid, int n, int m){
        vis[x][y] = 1;

        for(int i = 0; i < 4; i++){
            int nx = x + dx[i];
            int ny = y + dy[i];

            if(isValid(nx, ny, n, m) && !vis[nx][ny] && grid[nx][ny] == 0){
                dfs(nx, ny, vis, grid, n, m);
            }
        }

        
    }

    int regionsBySlashes(vector<string>& grid) {

        int n = grid.size();
        map<int, vector<int>> V;
        int strt = 0;
        for(int i = 0; i < n; i++){
            for(int j = 0; j < n; j++){
                char c = grid[i][j];

                if(c == ' '){

                    V[strt].push_back(0);
                    V[strt].push_back(0);
                    V[strt].push_back(0);
                    V[strt + 1].push_back(0);
                    V[strt + 1].push_back(0);
                    V[strt + 1].push_back(0);

                    V[strt + 2].push_back(0);
                    V[strt + 2].push_back(0);
                    V[strt + 2].push_back(0);
                    
                }

                if(c == '/'){
                   
                    vector<int> temp1 = {0, 1};
                    vector<int> temp2 = {1, 0};

                    V[strt].push_back(0);
                    V[strt].push_back(0);
                    V[strt].push_back(1);

                    V[strt + 1].push_back(0);
                    V[strt + 1].push_back(1);
                    V[strt + 1].push_back(0);

                    V[strt + 2].push_back(1);
                    V[strt + 2].push_back(0);
                    V[strt + 2].push_back(0);

                }
                if(c == '\\'){


                    V[strt].push_back(1);
                    V[strt].push_back(0);
                    V[strt].push_back(0);

                    V[strt + 1].push_back(0);
                    V[strt + 1].push_back(1);
                    V[strt + 1].push_back(0);

                    V[strt + 2].push_back(0);
                    V[strt + 2].push_back(0);
                    V[strt + 2].push_back(1);
                }

            }
            strt += 3;
        }

        int N = V.size();
        

        int count = 0;

        vector<vector<int>> vis(N, vector<int> (N));

        for(int i = 0; i < N; i++){
            for(int j = 0; j < N; j++){
                if(!vis[i][j] && V[i][j] == 0){
                    dfs(i, j, vis, V, N, N);
                    count++;
                }
            }
        }

        return count;

    }

};
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