<p>You are given an <code>m x n</code> binary grid <code>grid</code> where <code>1</code> represents land and <code>0</code> represents water. An <strong>island</strong> is a maximal <strong>4-directionally</strong> (horizontal or vertical) connected group of <code>1</code>&#39;s.</p>

<p>The grid is said to be <strong>connected</strong> if we have <strong>exactly one island</strong>, otherwise is said <strong>disconnected</strong>.</p>

<p>In one day, we are allowed to change <strong>any </strong>single land cell <code>(1)</code> into a water cell <code>(0)</code>.</p>

<p>Return <em>the minimum number of days to disconnect the grid</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/12/24/land1.jpg" style="width: 500px; height: 169px;" />
<pre>
<strong>Input:</strong> grid = [[0,1,1,0],[0,1,1,0],[0,0,0,0]]

<strong>Output:</strong> 2
<strong>Explanation:</strong> We need at least 2 days to get a disconnected grid.
Change land grid[1][1] and grid[0][2] to water and get 2 disconnected island.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/12/24/land2.jpg" style="width: 404px; height: 85px;" />
<pre>
<strong>Input:</strong> grid = [[1,1]]
<strong>Output:</strong> 2
<strong>Explanation:</strong> Grid of full water is also disconnected ([[1,1]] -&gt; [[0,0]]), 0 islands.
</pre>

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

<ul>
	<li><code>m == grid.length</code></li>
	<li><code>n == grid[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 30</code></li>
	<li><code>grid[i][j]</code> is either <code>0</code> or <code>1</code>.</li>
</ul>

class Solution {
public:
int countIslands(vector<vector<int>> grid)
{
    int n = grid.size();
    int m = grid[0].size();
    int dir[5] = {0,1,0,-1,0};
    int cnt = 0;
    vector<vector<int>> temp = grid;
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<m;j++)
        {
            if(temp[i][j] == 1)
            {
                cnt++;
                queue<pair<int,int>> q;
                q.push({i,j});
                temp[i][j] = 0;
                while(q.empty() == false)
                {
                    pair<int,int> tp = q.front();
                    q.pop();
                    for(int k=0;k<4;k++)
                    {
                        int x = tp.first + dir[k];
                        int y = tp.second + dir[k+1];
                        if(x >= 0 && x <= n-1 && y >= 0 && y <= m-1 && temp[x][y] == 1)
                        {
                            q.push({x,y});
                            temp[x][y] = 0;
                        }
                    }
                }
            }
        }
    }
    return cnt;
}
    int minDays(vector<vector<int>>& grid) {
        int n = grid.size();
        int m = grid[0].size();

        int cnt = countIslands(grid);
        if(cnt != 1)
            return 0;
        else
        {
            for(int i=0;i<n;i++)
            {
                for(int j=0;j<m;j++)
                {
                    if(grid[i][j] == 1)
                    {
                        grid[i][j] = 0;
                        cnt = countIslands(grid);
                        if(cnt != 1)
                            return 1;
                        grid[i][j] = 1;
                    }
                }
            }        
        }

        return 2;
    }
};
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