<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:
    enum dir {LEFT, RIGHT, UP, DOWN};

    void dfs(int i, int j, dir d, vector<string>& grid, vector<vector<vector<int>>>& vmatrix) {
        // cout << i << " " << j << endl;
        if (grid[i][j] == ' ') {
            vmatrix[i][j] = vector<int>(4,currRegion);
            if (i+1 < grid.size() && vmatrix[i+1][j][UP] == 0) dfs(i+1,j,UP,grid,vmatrix);
            // cout << i << j << endl;
            if (i-1 > -1 && vmatrix[i-1][j][DOWN] == 0)  dfs(i-1,j,DOWN,grid,vmatrix);
            if (j+1 < grid.size() && vmatrix[i][j+1][LEFT] == 0) dfs(i,j+1,LEFT,grid,vmatrix);
            if (j-1 > -1 && vmatrix[i][j-1][RIGHT] == 0) dfs(i,j-1,RIGHT,grid,vmatrix);
        }
        else if (grid[i][j] == '/') {
            if (d == LEFT || d == UP) {
                vmatrix[i][j][LEFT] = currRegion;
                vmatrix[i][j][UP] = currRegion;
                if (i-1 > -1 && vmatrix[i-1][j][DOWN] == 0) dfs(i-1,j,DOWN,grid,vmatrix);
                if (j-1 > -1 && vmatrix[i][j-1][RIGHT] == 0) dfs(i,j-1,RIGHT,grid,vmatrix);
            }
            if (d == RIGHT || d == DOWN) {
                vmatrix[i][j][RIGHT] = currRegion;
                vmatrix[i][j][DOWN] = currRegion;
                if (i+1 < grid.size() && vmatrix[i+1][j][UP] == 0) dfs(i+1,j,UP,grid,vmatrix);
                if (j+1 < grid.size() && vmatrix[i][j+1][LEFT] == 0) dfs(i,j+1,LEFT,grid,vmatrix);
            }
        }
        else {
            if (d == LEFT || d == DOWN) {
                vmatrix[i][j][LEFT] = currRegion;
                vmatrix[i][j][DOWN] = currRegion;
                if (i+1 < grid.size() && vmatrix[i+1][j][UP] == 0) dfs(i+1,j,UP,grid,vmatrix);
                if (j-1 > -1 && vmatrix[i][j-1][RIGHT] == 0) dfs(i,j-1,RIGHT,grid,vmatrix);
            }
            if (d == RIGHT || d == UP) {
                // cout << i << j << endl;
                vmatrix[i][j][RIGHT] = currRegion;
                vmatrix[i][j][UP] = currRegion;
                if (i-1 > -1 && vmatrix[i-1][j][DOWN] == 0) dfs(i-1,j,DOWN,grid,vmatrix);
                if (j+1 < grid.size() && vmatrix[i][j+1][LEFT] == 0) dfs(i,j+1,LEFT,grid,vmatrix);
            }
        }
    }
    int regionsBySlashes(vector<string>& grid) {
        vector<vector<vector<int>>> vmatrix(grid.size(),vector<vector<int>>(grid.size(),vector<int>(4,0)));
        currRegion = 0;
        // ++currRegion;
        // dfs(0,0,LEFT,grid,vmatrix);
        // cout << "HI " << vmatrix[1][0][LEFT] << endl;
        // cout << endl;
        for (int i = 0; i < grid.size(); ++i) {
            for (int j = 0; j < grid.size(); ++j) {
                if (vmatrix[i][j][LEFT] == 0) {
                    ++currRegion;
                    dfs(i,j,LEFT,grid,vmatrix);
                }
                if (vmatrix[i][j][RIGHT] == 0) {
                    ++currRegion;
                    dfs(i,j,RIGHT,grid,vmatrix);
                }
                // cout << currRegion << endl;
            }
            // cout << "HI " << vmatrix[1][0][LEFT] << endl;
            // cout << endl;
        }
        return currRegion;
    }
    int currRegion;
};
// \\\
// \\/
//  //

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