<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 find(int array[],int x)
    {
        if(array[x]==x)
            return x;
        return find(array,array[x]);
    }
    void unionds(int array[],int x,int y)
    {
        int xf=find(array,x);
        int yf=find(array,y);
        array[xf]=yf;
    }
    int regionsBySlashes(vector<string>& grid) {
        int n=grid.size();
        int parent[4*n*n];
        for(int i=0;i<4*n*n;i++)parent[i]=i;
        for(int row=0;row<n;row++)
        {
            int start=0;
            for(int col=0;col<n;col++)
            {
                int base=4*n*row + 4*col;

                if(grid[row][start]!='/')
                   {
                       unionds(parent,base,base+2);
                       unionds(parent,base+1,base+3);


                   }
                if(grid[row][start]!='\\')
                {
                    unionds(parent,base,base+1);
                    unionds(parent,base+2,base+3);
                }
                start++;
                if(col<n-1)
                    unionds(parent,base+2,base+5);
                if(row<n-1)
                    unionds(parent,base+3,4*n*(row+1)+4*col);
            }
        }
        int ans=0;
        for(int i=0;i<4*n*n;i++)
        {
            if(parent[i]==i)
                ans++;
        }
        return ans;
    }
};
11176