<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)
	{
		vector<string>newgrid(grid.size() * 3, string(grid[0].size() * 3, ' '));

		for (int i = 0; i < grid.size(); i++) {
			for (int j = 0; j < grid[0].size(); j++) {
				int newcol = j * 3;
				int newrow = i * 3;
				if (grid[i][j] == '/') {
					newgrid[newrow + 2][newcol] = '1'; 
					newgrid[newrow + 1][newcol + 1] = '1'; 
					newgrid[newrow][newcol + 2] = '1'; 
				}
				else if (grid[i][j] == '\\') {
					newgrid[newrow][newcol] = '1'; 
					newgrid[newrow + 1][newcol + 1] = '1'; 
					newgrid[newrow + 2][newcol + 2] = '1'; 
				}
			}
		}

		int count = 0; 
		for (int i = 0; i < newgrid.size(); i++) {
			for (int j = 0; j < newgrid[0].size(); j++) {
				if (newgrid[i][j] != '1') {
					count++; 
					BFS(newgrid, i, j); 
				}
			}
		}
		return count; 
	}
private:
	void BFS(vector<string>& grid, int startrow, int startcol)
	{
		grid[startrow][startcol] = '1'; 
		queue<pair<int, int>>Queue; 
		Queue.push(make_pair(startrow, startcol)); 

		while (Queue.size() != 0) {
			int currow = Queue.front().first; 
			int curcol = Queue.front().second; 
			Queue.pop(); 
			for (auto& dir : directions) {
				int nextrow = currow + dir[0]; 
				int nextcol = curcol + dir[1]; 
				if (nextrow >= 0 && nextrow < grid.size() && nextcol >= 0 && nextcol < grid[0].size() && grid[nextrow][nextcol] == ' ') {
					grid[nextrow][nextcol] = '1'; 
					Queue.push(make_pair(nextrow, nextcol)); 
				}
			}
		}
	}

	const vector<vector<int>>directions = { {1,0},{-1,0},{0,1},{0,-1} }; 
};
18648