<p>You are given an <code>m x n</code> matrix <code>board</code> containing <strong>letters</strong> <code>&#39;X&#39;</code> and <code>&#39;O&#39;</code>, <strong>capture regions</strong> that are <strong>surrounded</strong>:</p>

<ul>
	<li><strong>Connect</strong>: A cell is connected to adjacent cells horizontally or vertically.</li>
	<li><strong>Region</strong>: To form a region <strong>connect every</strong> <code>&#39;O&#39;</code> cell.</li>
	<li><strong>Surround</strong>: The region is surrounded with <code>&#39;X&#39;</code> cells if you can <strong>connect the region </strong>with <code>&#39;X&#39;</code> cells and none of the region cells are on the edge of the <code>board</code>.</li>
</ul>

<p>A <strong>surrounded region is captured</strong> by replacing all <code>&#39;O&#39;</code>s with <code>&#39;X&#39;</code>s in the input matrix <code>board</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">board = [[&quot;X&quot;,&quot;X&quot;,&quot;X&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;O&quot;,&quot;O&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;X&quot;,&quot;O&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;O&quot;,&quot;X&quot;,&quot;X&quot;]]</span></p>

<p><strong>Output:</strong> <span class="example-io">[[&quot;X&quot;,&quot;X&quot;,&quot;X&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;X&quot;,&quot;X&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;X&quot;,&quot;X&quot;,&quot;X&quot;],[&quot;X&quot;,&quot;O&quot;,&quot;X&quot;,&quot;X&quot;]]</span></p>

<p><strong>Explanation:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/xogrid.jpg" style="width: 367px; height: 158px;" />
<p>In the above diagram, the bottom region is not captured because it is on the edge of the board and cannot be surrounded.</p>
</div>

<p><strong class="example">Example 2:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">board = [[&quot;X&quot;]]</span></p>

<p><strong>Output:</strong> <span class="example-io">[[&quot;X&quot;]]</span></p>
</div>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>m == board.length</code></li>
	<li><code>n == board[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 200</code></li>
	<li><code>board[i][j]</code> is <code>&#39;X&#39;</code> or <code>&#39;O&#39;</code>.</li>
</ul>

class Solution {
    bool check(vector<vector<char>>& board, const int i, const int j, vector<char*> &v)
    {
        v.push_back(&board[i][j]);
        board[i][j]='A';
        bool edge{false};
        if(i>0)
        {
            if(board[i-1][j]=='O')
                edge=check(board,i-1,j,v);
        }
        else
            edge=true;
        if(j>0)
        {
            if(board[i][j-1]=='O')
                edge=check(board,i,j-1,v)||edge;
        }
        else
            edge=true;
        if(i<board.size()-1)
        {
             if(board[i+1][j]=='O')
                edge=check(board,i+1,j,v)||edge;
        }
        else
            edge=true;
        if(j<board[0].size()-1)
        {
             if(board[i][j+1]=='O')
                edge=check(board,i,j+1,v)||edge;
        }
        else
            edge=true;
        return edge;
            
    }
public:
    void solve(vector<vector<char>>& board) {
        vector  <vector<char*>> replaceX{};
        vector  <vector<char*>>  replaceO{};
        for(int i{0};i<board.size();++i)
        {
            for(int j{0};j<board[0].size();++j)
            {
                if(board[i][j]=='O')
                {
                   vector<char*> v{};
                    if(check(board,i,j,v))
     replaceO.push_back(v);
                    else
                        replaceX.push_back(v);
                }
                    
            }
        }
for(vector<char*> &v: replaceX)
{
   for(char* c:v)
       *c='X';
}
    for(vector<char*> &v: replaceO)
{
   for(char* c:v)
       *c='O';
}
    }
};
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