<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 {
private:
    void solution(vector<vector<int>>& grid, vector<vector<bool>>& visited, int row, int col) {
        if(row<0 || row>=grid.size() || col<0 || col>=grid[0].size() || grid[row][col] == 0 || visited[row][col])
            return;
        visited[row][col] = true;
        int rows[4] = {row, row, row+1, row-1};
        int cols[4] = {col+1, col-1, col, col};
        for(int i=0; i<4; i++)
            solution(grid, visited, rows[i], cols[i]);
    }
    int count(vector<vector<int>> &grid) {
        int ans = 0;
        vector<vector<bool>> visited(grid.size(), vector<bool>(grid[0].size(), false));
        for(int row=0; row<grid.size(); row++){
            for(int col=0; col<grid[0].size(); col++) {
                if(grid[row][col] == 1 && !visited[row][col]) {
                    ans++;
                    solution(grid, visited, row, col);
                }
            }
        }
        return ans;
    }
    bool check(vector<vector<int>>& grid, int row, int col) {
        if(row<0 || row>=grid.size() || col<0 || col>=grid[0].size())
            return 0;
        return grid[row][col];
    }
public:
    int minDays(vector<vector<int>>& grid) {
        int cnt = count(grid);
        int ans = 5;
        int r,c;
        if(cnt!=1) return 0;
        for(int row=0; row<grid.size(); row++) {
            for(int col=0; col<grid[0].size(); col++) {
                if(grid[row][col] == 1){    
                    grid[row][col] = 0;
                    if(count(grid) != 1)
                        return 1;
                     grid[row][col] = 1;
                    int rows[4] = {row, row, row+1, row-1};
                    int cols[4] = {col+1, col-1, col, col};
                    for(int i=0; i<4; i++) {
                        if(check(grid, rows[i], cols[i])) {
                            grid[rows[i]][cols[i]] = 0;
                            if(count(grid) != 1)
                                return 1;
                            grid[rows[i]][cols[i]] = 1;
                        }
                    }
                }
            }
        }
        return 2;
    }
};
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